Merge pull request 'feat(web): 多语言界面（中/英/日）与用户语言偏好字段' (#15) from dsh/mailgo:fix/legacy-ban-index into main

Reviewed-on: #15

README.md

@@ -9,6 +9,7 @@ Web frontend layout: top navigation + left folder sidebar + mail list (three-col
 
 - **Mail protocols**: SMTP (send), IMAP (sync), POP3 (receive), all with TLS support
 - **External delivery**: authenticated users can send mail to external addresses (Gmail/Outlook, etc.), with a built-in outbound queue, **concurrent worker pool delivery** (default 4 workers + max 2 concurrent connections per recipient domain), direct MX delivery, STARTTLS, exponential backoff retry, bounce notifications and DKIM signing
+- **Multi-language UI (i18n)**: Chinese / English / Japanese, selectable in user settings (or auto-follow the browser language via Accept-Language; English is the fallback), covering all user and admin pages, 12-hour time formats (AM/PM) and error messages
 - **Web mail**: folder data-driven (Web and IMAP share the same MailboxService — whatever IMAP LIST returns is what the UI shows), system folders (Inbox / Sent / Drafts / Trash) plus custom folder management, delete moves to Trash (with restore / permanent delete / empty Trash), unread badges and search filters, select-all / batch delete, sender avatars, rich text editing (Quill.js), attachment upload/download
 - **Admin console**: domain management, user management, automatic DKIM key generation, DNS configuration hints, full mail browsing, outbound queue management, IP ban management, dashboard statistics, all timestamps displayed as 12-hour format (AM/PM) in the web timezone
 - **Protocol call logs**: every SMTP/IMAP/POP3 connection automatically records source IP, username, success/failure, failure reason and operation summary; filterable by protocol/status/IP/user/time for analyzing password brute-force, relay abuse and other attacks (kept 30 days by default, auto-cleaned)

README_cn.md

@@ -9,6 +9,7 @@ Web 前端的布局：顶部导航 + 左侧文件夹栏 + 邮件列表三栏设
 
 - **邮件协议**：SMTP（发送）、IMAP（同步）、POP3（收取），均支持 TLS 加密
 - **外部投递**：认证用户可向外部邮箱（Gmail/Outlook 等）发送邮件，内置外发队列、**并发 worker 池投递**（默认 4 线程 + 每收件域并发上限 2）、MX 直投、STARTTLS、指数退避重试、退信通知与 DKIM 签名
+- **多语言界面（i18n）**：中文 / 英文 / 日文，在「设置」页可选择界面语言（或自动跟随浏览器 Accept-Language，英语兜底），覆盖全部用户页与管理后台、12 小时制时间与错误提示
 - **Web 邮箱**：文件夹数据驱动（Web 与 IMAP 共享 MailboxService，IMAP LIST 返回什么界面就显示什么），系统文件夹（收件箱 / 已发送 / 草稿箱 / 垃圾箱）与自定义文件夹管理、删除邮件移入垃圾箱（支持恢复 / 彻底删除 / 清空）、未读角标与搜索过滤、全选 / 批量删除、发件人头像、富文本编辑（Quill.js）、附件上传/下载
 - **管理后台**：域名管理、用户管理、DKIM 密钥自动生成、DNS 配置提示、全量邮件查看、外发队列管理、IP 封禁管理、仪表盘统计、时间统一按 Web 时区显示 12 小时制（上午/下午）
 - **协议调用日志**：SMTP / IMAP / POP3 每次连接自动记录来源 IP、用户名、成功/失败、失败原因与操作摘要，可按协议/状态/IP/用户名/时间筛选，用于分析密码爆破、中继滥用等攻击行为（默认保留 30 天，自动清理）

internal/db/models.go

@@ -18,6 +18,9 @@ type User struct {
 	// MustChangePassword 为 true 时该用户（通常是初始管理员或被重置密码的
 	// 用户）在首次登录后必须修改密码。
 	MustChangePassword bool `gorm:"default:false" json:"-"`
+	// Language 界面语言偏好：auto（跟随浏览器 Accept-Language）| en | zh | ja。
+	// 默认 auto，浏览器语言无法识别时回退英语。
+	Language  string    `gorm:"size:8;default:auto" json:"language"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 }

internal/i18n/catalog.go

@@ -0,0 +1,736 @@
+package i18n
+
+// en 英文目录：key 为界面中的原始中文字符串。
+// 英语是兜底语言：ja 缺译时回退这里，未知语言也回退这里。
+var en = map[string]string{
+	// ---------- 12 小时制时段（日期函数） ----------
+	"上午": "AM",
+	"下午": "PM",
+
+	// ---------- 系统文件夹名（folderLabel） ----------
+	"收件箱": "Inbox",
+	"已发送": "Sent",
+	"草稿箱": "Drafts",
+	"已删除": "Trash",
+
+	// ---------- 顶栏 / 侧栏（base.html） ----------
+	"邮箱":             "Mail",
+	"搜索邮件（发件人 / 主题）": "Search mail (sender / subject)",
+	"管理后台":           "Admin",
+	"设置":             "Settings",
+	"退出登录":           "Log out",
+	"写信":             "Compose",
+
+	// ---------- 邮件列表（folder.html） ----------
+	"全选/取消全选": "Select all / deselect all",
+	"全选":      "Select all",
+	"刷新":      "Refresh",
+	"删除":      "Delete",
+	"彻底删除":    "Delete permanently",
+	"确定要清空「已删除」文件夹吗？此操作不可恢复。": "Empty the Trash folder? This cannot be undone.",
+	"清空文件夹":       "Empty folder",
+	"共 %d 封":      "%d messages",
+	"暂无邮件":        "No messages",
+	"收件人：%s":      "To: %s",
+	"致：":          "To: ",
+	"(无主题)":       "(no subject)",
+	"[HTML 邮件]":   "[HTML email]",
+	"确定要恢复这封邮件吗？": "Restore this message?",
+	"恢复到收件箱":      "Restore to inbox",
+	"确定要删除这封邮件吗？": "Delete this message?",
+	"第 %d / %d 页": "Page %d of %d",
+	"上一页":         "Previous",
+	"下一页":         "Next",
+	"确定要删除选中的 %s 封邮件吗？": "Delete the %s selected message(s)?",
+
+	// ---------- 邮件阅读（view.html） ----------
+	"查看邮件": "View message",
+	"返回":   "Back",
+	"回复":   "Reply",
+	"恢复":   "Restore",
+	"确定要彻底删除这封邮件吗？此操作不可恢复。": "Permanently delete this message? This cannot be undone.",
+	"删除邮件": "Delete message",
+	"抄送：":  "Cc: ",
+
+	// ---------- 写信（compose.html） ----------
+	"发送":        "Send",
+	"附件":        "Attach",
+	"取消":        "Cancel",
+	"撰写新邮件":     "New message",
+	"收件人":       "To",
+	"输入收件人邮箱地址": "Recipient email address",
+	"抄送":        "Cc",
+	"多个地址用逗号分隔（可选）": "Separate multiple addresses with commas (optional)",
+	"主题":         "Subject",
+	"输入邮件主题":     "Email subject",
+	"请输入邮件内容...": "Enter your message...",
+	"附件配额":       "Attachment quota",
+	"移除":         "Remove",
+
+	// ---------- 设置（settings.html） ----------
+	"⚠️ 首次登录/密码已被重置，请立即修改密码后再继续使用邮箱功能。": "⚠️ First login / password has been reset. Please change your password before using the mailbox.",
+	"账号信息":          "Account info",
+	"已用 %s / 配额 %s": "Used %s / Quota %s",
+	"管理员":           "Admin",
+	"修改密码":          "Change password",
+	"当前密码":          "Current password",
+	"请输入当前密码":       "Enter current password",
+	"新密码":           "New password",
+	"请输入新密码":        "Enter new password",
+	"确认新密码":         "Confirm new password",
+	"请再次输入新密码":      "Re-enter new password",
+	"界面语言":          "Interface language",
+	"自动（跟随浏览器）":     "Auto (browser)",
+	"保存":            "Save",
+	"语言偏好已保存":       "Language preference saved",
+	"语言偏好保存失败":      "Failed to save language preference",
+	"帮助":            "Help",
+	"客户端收发信（IMAP / SMTP）配置：":        "IMAP / SMTP client settings:",
+	"IMAP 服务器：%s 端口 %d / SSL %d":    "IMAP server: %s port %d / SSL %d",
+	"SMTP 服务器：%s 端口 %d（提交）/ SSL %d": "SMTP server: %s port %d (submission) / SSL %d",
+
+	// ---------- 登录（login.html） ----------
+	"登录":       "Log in",
+	"登录您的邮箱账户": "Log in to your mailbox",
+	"邮箱地址":     "Email address",
+	"密码":       "Password",
+	"请输入密码":    "Enter password",
+	"登 录":      "Log in",
+	"或":        "or",
+	"LDAP 用户名": "LDAP username",
+	"LDAP 密码":  "LDAP password",
+	"LDAP 登录":  "LDAP sign in",
+
+	// ---------- 封禁页（banned.html） ----------
+	"访问被禁止":          "Access denied",
+	"您的 IP 已被暂时禁止访问": "Your IP has been temporarily blocked",
+	"由于登录失败次数过多，您的 IP 地址已被暂时封禁。": "Your IP address has been temporarily banned due to too many failed login attempts.",
+	"IP 地址":    "IP address",
+	"封禁档位":     "Ban level",
+	"第 %d 次封禁": "Ban #%d",
+	"原因":       "Reason",
+	"失败次数":     "Failed attempts",
+	"%d 次":     "%d times",
+	"解封时间":     "Unban time",
+	"请在解封时间后重试，或联系管理员。": "Please retry after the unban time, or contact the administrator.",
+	"返回登录页": "Back to login",
+
+	// ---------- 管理后台侧栏（所有 admin 页面） ----------
+	"返回邮箱":  "Back to mailbox",
+	"控制面板":  "Dashboard",
+	"域名管理":  "Domains",
+	"用户管理":  "Users",
+	"所有邮件":  "All mail",
+	"外发队列":  "Outbound queue",
+	"协议日志":  "Protocol logs",
+	"当前连接":  "Connections",
+	"IP黑名单": "IP blacklist",
+
+	// ---------- 控制面板（dashboard.html） ----------
+	"域名数":    "Domains",
+	"用户数":    "Users",
+	"邮件总数":   "Total mail",
+	"被封IP":   "Banned IPs",
+	"邮件分布":   "Mail distribution",
+	"文件夹":    "Folder",
+	"邮件数":    "Messages",
+	"占用空间":   "Size",
+	"合计":     "Total",
+	"收发统计":   "Send/receive stats",
+	"时间段":    "Period",
+	"收件":     "Received",
+	"发件":     "Sent",
+	"今日":     "Today",
+	"近 7 天":  "Last 7 days",
+	"快捷操作":   "Quick actions",
+	"新增域名":   "Add domain",
+	"新增用户":   "Add user",
+	"查看所有邮件": "View all mail",
+
+	// ---------- 用户管理（users.html / user_form.html） ----------
+	"用户列表":          "Users",
+	"暂无用户":          "No users",
+	"用户名":           "Username",
+	"域名ID":          "Domain ID",
+	"配额":            "Quota",
+	"已用":            "Used",
+	"状态":            "Status",
+	"操作":            "Actions",
+	"编辑":            "Edit",
+	"确定要删除用户 %s 吗？": "Delete user %s?",
+	"编辑用户":          "Edit user",
+	"新密码（留空则不修改）":   "New password (leave blank to keep)",
+	"域名":            "Domain",
+	"请选择域名":         "Select a domain",
+	"配额 (GB)":       "Quota (GB)",
+	"启用账户":          "Active account",
+	"保存更改":          "Save changes",
+	"创建用户":          "Create user",
+
+	// ---------- 域名管理（domains.html / domain_form.html / dns_hint.html） ----------
+	"域名列表": "Domains",
+	"暂无域名": "No domains",
+	"确定要删除域名 %s 吗？删除域名将导致关联用户无法收发邮件！": "Delete domain %s? Users of this domain will no longer be able to send or receive mail!",
+	"编辑域名":    "Edit domain",
+	"SMTP 端口": "SMTP port",
+	"IMAP 端口": "IMAP port",
+	"POP3 端口": "POP3 port",
+	"启用 TLS":  "Enable TLS",
+	"勾选后端口将自动切换为 SSL/TLS 标准端口": "When checked, ports switch to standard SSL/TLS ports automatically",
+	"TLS 私钥 PEM":   "TLS private key (PEM)",
+	"TLS 公钥证书 PEM": "TLS certificate (PEM)",
+	"私钥不会回显；留空则保留现有私钥。":                 "The private key is not shown; leave blank to keep the current key.",
+	"✅ TLS 证书已配置；上传新证书后自动热加载生效。":        "✅ Certificate configured; uploading a new certificate hot-reloads automatically.",
+	"⚠️ TLS 证书未配置，启用 TLS 时必须同时填写私钥和证书。": "⚠️ No certificate configured. To enable TLS you must provide both the private key and the certificate.",
+	"从 Caddy 获取证书": "Fetch certificate from Caddy",
+	"若该域名已由本机 Caddy 托管 HTTPS（自动签发证书），可一键导入其证书与私钥，并自动启用 TLS；证书热加载，无需重启服务。": "If this domain is served by local Caddy with HTTPS (automatic certificates), import its certificate and private key with one click; TLS is enabled and hot-reloaded, no restart needed.",
+	"🔒 从 Caddy 获取证书": "🔒 Fetch certificate from Caddy",
+	"获取中…":           "Fetching...",
+	"获取失败":           "Fetch failed",
+	"请求失败":           "Request failed",
+	"重新生成 DKIM 密钥":   "Regenerate DKIM key",
+	"✅ DKIM 密钥已配置":   "✅ DKIM key configured",
+	"⚠️ DKIM 密钥未配置":  "⚠️ DKIM key not configured",
+	"创建域名":           "Create domain",
+	"DNS配置":          "DNS configuration",
+	"DNS 配置提示 — %s":  "DNS configuration hint — %s",
+	"请在您的 DNS 服务商处添加以下记录：": "Add the following records at your DNS provider:",
+	"MX 记录":         "MX record",
+	"SPF 记录 (TXT)":  "SPF record (TXT)",
+	"DKIM 记录 (TXT)": "DKIM record (TXT)",
+	"DMARC 记录":      "DMARC record",
+	"⚠️ DKIM 密钥尚未生成，请编辑域名重新生成。": "⚠️ DKIM key not generated yet. Edit the domain to regenerate it.",
+	"返回域名列表": "Back to domains",
+
+	// ---------- 所有邮件（mails.html / mail_view.html） ----------
+	"发件人":    "From",
+	"所属用户":   "Owner",
+	"日期":     "Date",
+	"全部":     "All",
+	"返回邮件列表": "Back to list",
+	"发件人:":   "From:",
+	"收件人:":   "To:",
+	"抄送:":    "Cc:",
+	"所属用户:":  "Owner:",
+	"文件夹:":   "Folder:",
+	"时间:":    "Time:",
+	"附件列表":   "Attachments",
+
+	// ---------- 外发队列（outbound.html） ----------
+	"队列为空":       "Queue is empty",
+	"待发送":        "Pending",
+	"发送中":        "Sending",
+	"已送达":        "Delivered",
+	"等待重试":       "Waiting to retry",
+	"失败":         "Failed",
+	"已取消":        "Canceled",
+	"尝试次数":       "Attempts",
+	"下次重试":       "Next retry",
+	"最后响应 / 错误":  "Last response / error",
+	"创建时间":       "Created",
+	"重试":         "Retry",
+	"确认取消该投递任务？": "Cancel this delivery task?",
+
+	// ---------- 协议日志（protocol_logs.html） ----------
+	"协议日志（SMTP / IMAP / POP3）": "Protocol logs (SMTP / IMAP / POP3)",
+	"清理旧日志":                    "Clean old logs",
+	"确认清理 %d 天前的协议日志？":         "Delete protocol logs older than %d days?",
+	"今日 SMTP 失败":               "SMTP failures today",
+	"今日 IMAP 失败":               "IMAP failures today",
+	"今日 POP3 失败":               "POP3 failures today",
+	"历史失败（全部）":                 "Historical failures (all)",
+	"全部协议":                     "All protocols",
+	"全部状态":                     "All statuses",
+	"成功":                       "Success",
+	"来源 IP（模糊）":                "Source IP (fuzzy)",
+	"用户名（模糊）":                  "Username (fuzzy)",
+	"至":                        "to",
+	"筛选":                       "Filter",
+	"重置":                       "Reset",
+	"时间":                       "Time",
+	"端口":                       "Port",
+	"失败原因":                     "Failure reason",
+	"操作摘要":                     "Summary",
+	"消息数":                      "Messages",
+	"时长":                       "Duration",
+	"暂无记录":                     "No records",
+	"第 %d / %d 页（共 %d 条）":      "Page %d of %d (%d entries)",
+
+	// ---------- 当前连接（connections.html） ----------
+	"当前连接（SMTP / IMAP / POP3）": "Active connections (SMTP / IMAP / POP3)",
+	"每 5 秒自动刷新":                "Auto-refreshes every 5 seconds",
+	"当前连接总数":                   "Total active connections",
+	"协议":                       "Protocol",
+	"来源 IP":                    "Source IP",
+	"TLS":                      "TLS",
+	"明文":                       "Plain",
+	"连接时间":                     "Connected",
+	"最后活跃":                     "Last active",
+	"断开并封禁":                    "Disconnect & ban",
+	"当前没有活动连接":                 "No active connections",
+	"确定要断开 IP %s 的所有连接并加入黑名单（180 天）吗？": "Disconnect all connections of IP %s and add to blacklist (180 days)?",
+
+	// ---------- IP 黑名单（bans.html） ----------
+	"IP 黑名单": "IP blacklist",
+	"阶段性封禁：第 4 次触发起封禁，30分钟 → 3小时 → 3个月 → 半年（上限）": "Staged bans: banning starts at the 4th trigger; 30 min → 3 h → 3 mo → 6 mo (max)",
+	"封禁次数":  "Ban count",
+	"到期时间":  "Expires",
+	"封禁中":   "Banned",
+	"已过期":   "Expired",
+	"仅计数":   "Counting only",
+	"（已过期）": " (expired)",
+	"解封":    "Unban",
+	"确定要解封 IP %s 吗？解封后该 IP 的封禁档位将清零。": "Unban IP %s? Its ban level will be reset.",
+	"暂无封禁记录": "No ban records",
+
+	// ---------- 登录/认证错误（auth.go） ----------
+	"请输入邮箱和密码":                  "Please enter your email and password",
+	"用户名或密码错误，还剩 %d 次尝试机会":      "Incorrect username or password. %d attempts remaining",
+	"会话保存失败，请重试":                "Failed to save session, please retry",
+	"请输入LDAP用户名和密码":             "Please enter your LDAP username and password",
+	"LDAP 认证失败，还剩 %d 次尝试机会":     "LDAP authentication failed. %d attempts remaining",
+	"LDAP 账号未接入本系统，请联系管理员":      "LDAP account is not linked to this system. Contact the administrator",
+	"用户已被禁用":                    "User is disabled",
+	"OAuth2 state 校验失败，请重新发起登录": "OAuth2 state validation failed, please log in again",
+	"OAuth2 授权码缺失":              "Missing OAuth2 authorization code",
+	"OAuth2 认证失败，请重试或联系管理员":     "OAuth2 authentication failed. Please retry or contact the administrator",
+	"OAuth2 账号未接入本系统，请联系管理员":    "OAuth2 account is not linked to this system. Contact the administrator",
+	"OAuth2 未启用":                "OAuth2 is not enabled",
+	"OAuth2 登录暂不可用，请稍后重试":       "OAuth2 login is temporarily unavailable, please try again later",
+	"登录失败次数过多":                  "Too many failed login attempts",
+	"LDAP 登录失败次数过多":             "Too many LDAP login failures",
+
+	// ---------- 邮件操作错误（mail.go） ----------
+	"请输入收件人":                  "Please enter a recipient",
+	"配额检查失败，请稍后重试":            "Quota check failed, please try again later",
+	"附件超出配额限制。已用 %s / 总配额 %s": "Attachments exceed the quota. Used %s / total %s",
+	"外部投递未启用":                 "Outbound delivery is not enabled",
+	"外部收件人过多：最多 %d 个":         "Too many external recipients: maximum %d",
+	"外发邮件入队失败 (%s): %v":       "Failed to enqueue outbound mail (%s): %v",
+	"投递邮件失败: %v":              "Failed to deliver mail: %v",
+	"保存邮件失败: %v":              "Failed to save mail: %v",
+	"当前密码不正确":                 "Current password is incorrect",
+	"新密码不能为空":                 "New password cannot be empty",
+	"两次输入的密码不一致":              "The two passwords do not match",
+	"密码加密失败":                  "Failed to encrypt password",
+	"密码更新失败":                  "Failed to update password",
+	"密码修改成功":                  "Password changed successfully",
+	"邮箱不存在":                   "Mailbox does not exist",
+	"加载邮件列表失败: %v":            "Failed to load messages: %v",
+	"无效的邮件ID":                 "Invalid message ID",
+	"邮件不存在":                   "Message does not exist",
+	"禁止访问":                    "Access denied",
+	"无效的附件ID":                 "Invalid attachment ID",
+	"附件不存在":                   "Attachment does not exist",
+	"读取附件失败":                  "Failed to read attachment",
+	"删除失败":                    "Delete failed",
+	"恢复失败":                    "Restore failed",
+	"清空文件夹失败: %v":             "Failed to empty folder: %v",
+
+	// ---------- 管理操作错误（admin.go） ----------
+	"无效的连接ID":       "Invalid connection ID",
+	"连接不存在或已断开":     "Connection does not exist or is disconnected",
+	"管理员手动封禁（连接断开）": "Banned manually by admin (connection disconnected)",
+	"封禁失败: %v":      "Ban failed: %v",
+	"加载域名列表失败: %v":  "Failed to load domains: %v",
+	"请输入域名":         "Please enter a domain name",
+	"创建域名失败: %v":    "Failed to create domain: %v",
+	"无效的域名ID":       "Invalid domain ID",
+	"域名不存在":         "Domain does not exist",
+	"✅ 已从 Caddy 获取证书并保存到域名 TLS 目录，同时已启用该域名的 TLS；证书已热加载，无需重启服务。": "✅ Certificate fetched from Caddy and saved to the domain TLS directory; TLS enabled and hot-reloaded, no restart needed.",
+	"启用 TLS 时必须填写 TLS 私钥和公钥证书": "TLS private key and certificate are required to enable TLS",
+	"TLS 私钥和公钥证书必须同时填写":        "TLS private key and certificate must be provided together",
+	"TLS 证书或私钥无效: %v":          "Invalid TLS certificate or private key: %v",
+	"创建 TLS 证书目录失败: %v":        "Failed to create TLS directory: %v",
+	"保存 TLS 公钥证书失败: %v":        "Failed to save TLS certificate: %v",
+	"保存 TLS 私钥失败: %v":          "Failed to save TLS private key: %v",
+	"从 Caddy 获取证书失败: %v":       "Failed to fetch certificate from Caddy: %v",
+	"更新域名记录失败: %v":             "Failed to update domain record: %v",
+	"更新域名失败: %v":               "Failed to update domain: %v",
+	"删除域名失败: %v":               "Failed to delete domain: %v",
+	"加载用户列表失败: %v":             "Failed to load users: %v",
+	"请填写所有必填字段":                "Please fill in all required fields",
+	"创建用户失败: %v":               "Failed to create user: %v",
+	"无效的用户ID":                  "Invalid user ID",
+	"不能删除自己的账户":                "You cannot delete your own account",
+	"删除用户失败: %v":               "Failed to delete user: %v",
+	"用户不存在":                    "User does not exist",
+	"更新用户失败: %v":               "Failed to update user: %v",
+	"加载黑名单失败: %v":              "Failed to load blacklist: %v",
+	"无效的记录ID":                  "Invalid record ID",
+	"解封失败: %v":                 "Unban failed: %v",
+	"加载协议日志失败: %v":             "Failed to load protocol logs: %v",
+	"加载外发队列失败: %v":             "Failed to load outbound queue: %v",
+	"外发服务不可用":                  "Outbound service is unavailable",
+	"重试失败: %v":                 "Retry failed: %v",
+	"取消失败: %v":                 "Cancel failed: %v",
+	"无效的队列ID":                  "Invalid queue ID",
+	"禁止访问：需要管理员权限":             "Access denied: administrator privileges required",
+}
+
+// ja 日文目录：key 为界面中的原始中文字符串；缺译回退英文目录。
+var ja = map[string]string{
+	// ---------- 12 小时制时段（日期函数） ----------
+	"上午": "午前",
+	"下午": "午後",
+
+	// ---------- 系统文件夹名（folderLabel） ----------
+	"收件箱": "受信トレイ",
+	"已发送": "送信済み",
+	"草稿箱": "下書き",
+	"已删除": "ゴミ箱",
+
+	// ---------- 顶栏 / 侧栏（base.html） ----------
+	"邮箱":             "メール",
+	"搜索邮件（发件人 / 主题）": "メールを検索（送信者 / 件名）",
+	"管理后台":           "管理画面",
+	"设置":             "設定",
+	"退出登录":           "ログアウト",
+	"写信":             "作成",
+
+	// ---------- 邮件列表（folder.html） ----------
+	"全选/取消全选": "すべて選択 / 選択解除",
+	"全选":      "すべて選択",
+	"刷新":      "更新",
+	"删除":      "削除",
+	"彻底删除":    "完全に削除",
+	"确定要清空「已删除」文件夹吗？此操作不可恢复。": "「ゴミ箱」フォルダを空にしますか？この操作は元に戻せません。",
+	"清空文件夹":       "フォルダを空にする",
+	"共 %d 封":      "%d 件",
+	"暂无邮件":        "メールはありません",
+	"收件人：%s":      "宛先：%s",
+	"致：":          "宛先：",
+	"(无主题)":       "（件名なし）",
+	"[HTML 邮件]":   "[HTML メール]",
+	"确定要恢复这封邮件吗？": "このメールを復元しますか？",
+	"恢复到收件箱":      "受信トレイへ復元",
+	"确定要删除这封邮件吗？": "このメールを削除しますか？",
+	"第 %d / %d 页": "%d / %d ページ",
+	"上一页":         "前へ",
+	"下一页":         "次へ",
+	"确定要删除选中的 %s 封邮件吗？": "選択した %s 件のメールを削除しますか？",
+
+	// ---------- 邮件阅读（view.html） ----------
+	"查看邮件": "メールを表示",
+	"返回":   "戻る",
+	"回复":   "返信",
+	"恢复":   "復元",
+	"确定要彻底删除这封邮件吗？此操作不可恢复。": "このメールを完全に削除しますか？この操作は元に戻せません。",
+	"删除邮件": "メールを削除",
+	"抄送：":  "Cc：",
+
+	// ---------- 写信（compose.html） ----------
+	"发送":        "送信",
+	"附件":        "添付",
+	"取消":        "キャンセル",
+	"撰写新邮件":     "新しいメールを作成",
+	"收件人":       "宛先",
+	"输入收件人邮箱地址": "宛先メールアドレスを入力",
+	"抄送":        "Cc",
+	"多个地址用逗号分隔（可选）": "複数のアドレスはカンマ区切り（任意）",
+	"主题":         "件名",
+	"输入邮件主题":     "メールの件名を入力",
+	"请输入邮件内容...": "メール本文を入力してください...",
+	"附件配额":       "添付ファイル容量",
+	"移除":         "削除",
+
+	// ---------- 设置（settings.html） ----------
+	"⚠️ 首次登录/密码已被重置，请立即修改密码后再继续使用邮箱功能。": "⚠️ 初回ログインまたはパスワードリセット後です。メール機能を利用する前にパスワードを変更してください。",
+	"账号信息":          "アカウント情報",
+	"已用 %s / 配额 %s": "使用 %s / 容量 %s",
+	"管理员":           "管理者",
+	"修改密码":          "パスワード変更",
+	"当前密码":          "現在のパスワード",
+	"请输入当前密码":       "現在のパスワードを入力",
+	"新密码":           "新しいパスワード",
+	"请输入新密码":        "新しいパスワードを入力",
+	"确认新密码":         "新しいパスワード（確認）",
+	"请再次输入新密码":      "新しいパスワードを再入力",
+	"界面语言":          "表示言語",
+	"自动（跟随浏览器）":     "自動（ブラウザに従う）",
+	"保存":            "保存",
+	"语言偏好已保存":       "言語設定を保存しました",
+	"语言偏好保存失败":      "言語設定の保存に失敗しました",
+	"帮助":            "ヘルプ",
+	"客户端收发信（IMAP / SMTP）配置：":        "クライアント設定（IMAP / SMTP）：",
+	"IMAP 服务器：%s 端口 %d / SSL %d":    "IMAP サーバー：%s ポート %d / SSL %d",
+	"SMTP 服务器：%s 端口 %d（提交）/ SSL %d": "SMTP サーバー：%s ポート %d（サブミッション）/ SSL %d",
+
+	// ---------- 登录（login.html） ----------
+	"登录":       "ログイン",
+	"登录您的邮箱账户": "メールアカウントにログイン",
+	"邮箱地址":     "メールアドレス",
+	"密码":       "パスワード",
+	"请输入密码":    "パスワードを入力",
+	"登 录":      "ログイン",
+	"或":        "または",
+	"LDAP 用户名": "LDAP ユーザー名",
+	"LDAP 密码":  "LDAP パスワード",
+	"LDAP 登录":  "LDAP ログイン",
+
+	// ---------- 封禁页（banned.html） ----------
+	"访问被禁止":          "アクセスが禁止されています",
+	"您的 IP 已被暂时禁止访问": "お使いの IP は一時的にアクセス禁止されています",
+	"由于登录失败次数过多，您的 IP 地址已被暂时封禁。": "ログイン失敗が多すぎるため、IP アドレスが一時的にブロックされています。",
+	"IP 地址":    "IP アドレス",
+	"封禁档位":     "ブロック段階",
+	"第 %d 次封禁": "%d 回目のブロック",
+	"原因":       "理由",
+	"失败次数":     "失敗回数",
+	"%d 次":     "%d 回",
+	"解封时间":     "ブロック解除時刻",
+	"请在解封时间后重试，或联系管理员。": "ブロック解除後にもう一度お試しいただくか、管理者に連絡してください。",
+	"返回登录页": "ログインページに戻る",
+
+	// ---------- 管理后台侧栏（所有 admin 页面） ----------
+	"返回邮箱":  "メールボックスに戻る",
+	"控制面板":  "ダッシュボード",
+	"域名管理":  "ドメイン管理",
+	"用户管理":  "ユーザー管理",
+	"所有邮件":  "すべてのメール",
+	"外发队列":  "送信キュー",
+	"协议日志":  "プロトコルログ",
+	"当前连接":  "現在の接続",
+	"IP黑名单": "IP ブラックリスト",
+
+	// ---------- 控制面板（dashboard.html） ----------
+	"域名数":    "ドメイン数",
+	"用户数":    "ユーザー数",
+	"邮件总数":   "メール総数",
+	"被封IP":   "ブロック済み IP",
+	"邮件分布":   "メール分布",
+	"文件夹":    "フォルダ",
+	"邮件数":    "メール数",
+	"占用空间":   "使用容量",
+	"合计":     "合計",
+	"收发统计":   "送受信統計",
+	"时间段":    "期間",
+	"收件":     "受信",
+	"发件":     "送信",
+	"今日":     "今日",
+	"近 7 天":  "過去 7 日間",
+	"快捷操作":   "クイック操作",
+	"新增域名":   "ドメインを追加",
+	"新增用户":   "ユーザーを追加",
+	"查看所有邮件": "すべてのメールを表示",
+
+	// ---------- 用户管理（users.html / user_form.html） ----------
+	"用户列表":          "ユーザー一覧",
+	"暂无用户":          "ユーザーはいません",
+	"用户名":           "ユーザー名",
+	"域名ID":          "ドメイン ID",
+	"配额":            "容量",
+	"已用":            "使用量",
+	"状态":            "状態",
+	"操作":            "操作",
+	"编辑":            "編集",
+	"确定要删除用户 %s 吗？": "ユーザー %s を削除しますか？",
+	"编辑用户":          "ユーザーを編集",
+	"新密码（留空则不修改）":   "新しいパスワード（空欄なら変更なし）",
+	"域名":            "ドメイン",
+	"请选择域名":         "ドメインを選択",
+	"配额 (GB)":       "容量 (GB)",
+	"启用账户":          "アカウントを有効にする",
+	"保存更改":          "変更を保存",
+	"创建用户":          "ユーザーを作成",
+
+	// ---------- 域名管理（domains.html / domain_form.html / dns_hint.html） ----------
+	"域名列表": "ドメイン一覧",
+	"暂无域名": "ドメインはありません",
+	"确定要删除域名 %s 吗？删除域名将导致关联用户无法收发邮件！": "ドメイン %s を削除しますか？関連ユーザーはメールの送受信ができなくなります！",
+	"编辑域名":    "ドメインを編集",
+	"SMTP 端口": "SMTP ポート",
+	"IMAP 端口": "IMAP ポート",
+	"POP3 端口": "POP3 ポート",
+	"启用 TLS":  "TLS を有効にする",
+	"勾选后端口将自动切换为 SSL/TLS 标准端口": "チェックするとポートは標準の SSL/TLS ポートに自動的に切り替わります",
+	"TLS 私钥 PEM":   "TLS 秘密鍵 (PEM)",
+	"TLS 公钥证书 PEM": "TLS 公開鍵証明書 (PEM)",
+	"私钥不会回显；留空则保留现有私钥。":                 "秘密鍵は表示されません。空欄の場合は現在の鍵を保持します。",
+	"✅ TLS 证书已配置；上传新证书后自动热加载生效。":        "✅ 証明書は設定済みです。新しい証明書をアップロードすると自動的にホットリロードされます。",
+	"⚠️ TLS 证书未配置，启用 TLS 时必须同时填写私钥和证书。": "⚠️ 証明書が未設定です。TLS を有効にするには秘密鍵と証明書の両方が必要です。",
+	"从 Caddy 获取证书": "Caddy から証明書を取得",
+	"若该域名已由本机 Caddy 托管 HTTPS（自动签发证书），可一键导入其证书与私钥，并自动启用 TLS；证书热加载，无需重启服务。": "このドメインがローカル Caddy で HTTPS 運用されている場合（自動証明書）、証明書と秘密鍵をワンクリックでインポートし、TLS を自動で有効化します。ホットリロードされるため再起動は不要です。",
+	"🔒 从 Caddy 获取证书": "🔒 Caddy から証明書を取得",
+	"获取中…":           "取得中...",
+	"获取失败":           "取得失敗",
+	"请求失败":           "リクエスト失敗",
+	"重新生成 DKIM 密钥":   "DKIM キーを再生成",
+	"✅ DKIM 密钥已配置":   "✅ DKIM キー設定済み",
+	"⚠️ DKIM 密钥未配置":  "⚠️ DKIM キー未設定",
+	"创建域名":           "ドメインを作成",
+	"DNS配置":          "DNS 設定",
+	"DNS 配置提示 — %s":  "DNS 設定ヒント — %s",
+	"请在您的 DNS 服务商处添加以下记录：": "DNS プロバイダーで次のレコードを追加してください：",
+	"MX 记录":         "MX レコード",
+	"SPF 记录 (TXT)":  "SPF レコード (TXT)",
+	"DKIM 记录 (TXT)": "DKIM レコード (TXT)",
+	"DMARC 记录":      "DMARC レコード",
+	"⚠️ DKIM 密钥尚未生成，请编辑域名重新生成。": "⚠️ DKIM キーが未生成です。ドメインを編集して再生成してください。",
+	"返回域名列表": "ドメイン一覧に戻る",
+
+	// ---------- 所有邮件（mails.html / mail_view.html） ----------
+	"发件人":    "送信者",
+	"所属用户":   "所有者",
+	"日期":     "日付",
+	"全部":     "すべて",
+	"返回邮件列表": "一覧に戻る",
+	"发件人:":   "送信者：",
+	"收件人:":   "宛先：",
+	"抄送:":    "Cc：",
+	"所属用户:":  "所有者：",
+	"文件夹:":   "フォルダ：",
+	"时间:":    "時刻：",
+	"附件列表":   "添付ファイル",
+
+	// ---------- 外发队列（outbound.html） ----------
+	"队列为空":       "キューは空です",
+	"待发送":        "待機中",
+	"发送中":        "送信中",
+	"已送达":        "送信済み",
+	"等待重试":       "再試行待ち",
+	"失败":         "失敗",
+	"已取消":        "キャンセル済み",
+	"尝试次数":       "試行回数",
+	"下次重试":       "次回再試行",
+	"最后响应 / 错误":  "最終レスポンス / エラー",
+	"创建时间":       "作成日時",
+	"重试":         "再試行",
+	"确认取消该投递任务？": "この配信タスクをキャンセルしますか？",
+
+	// ---------- 协议日志（protocol_logs.html） ----------
+	"协议日志（SMTP / IMAP / POP3）": "プロトコルログ（SMTP / IMAP / POP3）",
+	"清理旧日志":                    "古いログを削除",
+	"确认清理 %d 天前的协议日志？":         "%d 日前より前のプロトコルログを削除しますか？",
+	"今日 SMTP 失败":               "今日の SMTP 失敗",
+	"今日 IMAP 失败":               "今日の IMAP 失敗",
+	"今日 POP3 失败":               "今日の POP3 失敗",
+	"历史失败（全部）":                 "過去の失敗（すべて）",
+	"全部协议":                     "すべてのプロトコル",
+	"全部状态":                     "すべての状態",
+	"成功":                       "成功",
+	"来源 IP（模糊）":                "送信元 IP（あいまい）",
+	"用户名（模糊）":                  "ユーザー名（あいまい）",
+	"至":                        "〜",
+	"筛选":                       "フィルター",
+	"重置":                       "リセット",
+	"时间":                       "時刻",
+	"端口":                       "ポート",
+	"失败原因":                     "失敗理由",
+	"操作摘要":                     "操作概要",
+	"消息数":                      "メッセージ数",
+	"时长":                       "所要時間",
+	"暂无记录":                     "記録はありません",
+	"第 %d / %d 页（共 %d 条）":      "%d / %d ページ（全 %d 件）",
+
+	// ---------- 当前连接（connections.html） ----------
+	"当前连接（SMTP / IMAP / POP3）": "現在の接続（SMTP / IMAP / POP3）",
+	"每 5 秒自动刷新":                "5 秒ごとに自動更新",
+	"当前连接总数":                   "現在の接続数",
+	"协议":                       "プロトコル",
+	"来源 IP":                    "送信元 IP",
+	"TLS":                      "TLS",
+	"明文":                       "平文",
+	"连接时间":                     "接続時刻",
+	"最后活跃":                     "最終アクティブ",
+	"断开并封禁":                    "切断してブロック",
+	"当前没有活动连接":                 "アクティブな接続はありません",
+	"确定要断开 IP %s 的所有连接并加入黑名单（180 天）吗？": "IP %s のすべての接続を切断してブラックリストに追加しますか（180 日）？",
+
+	// ---------- IP 黑名单（bans.html） ----------
+	"IP 黑名单": "IP ブラックリスト",
+	"阶段性封禁：第 4 次触发起封禁，30分钟 → 3小时 → 3个月 → 半年（上限）": "段階的ブロック：4 回目の発動からブロック開始、30分 → 3時間 → 3か月 → 半年（上限）",
+	"封禁次数":  "ブロック回数",
+	"到期时间":  "解除時刻",
+	"封禁中":   "ブロック中",
+	"已过期":   "期限切れ",
+	"仅计数":   "カウントのみ",
+	"（已过期）": "（期限切れ）",
+	"解封":    "解除",
+	"确定要解封 IP %s 吗？解封后该 IP 的封禁档位将清零。": "IP %s のブロックを解除しますか？ブロック段階はリセットされます。",
+	"暂无封禁记录": "ブロック記録はありません",
+
+	// ---------- 登录/认证错误（auth.go） ----------
+	"请输入邮箱和密码":                  "メールアドレスとパスワードを入力してください",
+	"用户名或密码错误，还剩 %d 次尝试机会":      "ユーザー名またはパスワードが違います。あと %d 回試行できます",
+	"会话保存失败，请重试":                "セッションの保存に失敗しました。もう一度お試しください",
+	"请输入LDAP用户名和密码":             "LDAP ユーザー名とパスワードを入力してください",
+	"LDAP 认证失败，还剩 %d 次尝试机会":     "LDAP 認証に失敗しました。あと %d 回試行できます",
+	"LDAP 账号未接入本系统，请联系管理员":      "LDAP アカウントはこのシステムに接続されていません。管理者に連絡してください",
+	"用户已被禁用":                    "ユーザーは無効です",
+	"OAuth2 state 校验失败，请重新发起登录": "OAuth2 の state 検証に失敗しました。もう一度ログインしてください",
+	"OAuth2 授权码缺失":              "OAuth2 認可コードがありません",
+	"OAuth2 认证失败，请重试或联系管理员":     "OAuth2 認証に失敗しました。再試行するか管理者に連絡してください",
+	"OAuth2 账号未接入本系统，请联系管理员":    "OAuth2 アカウントはこのシステムに接続されていません。管理者に連絡してください",
+	"OAuth2 未启用":                "OAuth2 は有効ではありません",
+	"OAuth2 登录暂不可用，请稍后重试":       "OAuth2 ログインは一時的に利用できません。後でもう一度お試しください",
+	"登录失败次数过多":                  "ログイン失敗が多すぎます",
+	"LDAP 登录失败次数过多":             "LDAP ログイン失敗が多すぎます",
+
+	// ---------- 邮件操作错误（mail.go） ----------
+	"请输入收件人":                  "宛先を入力してください",
+	"配额检查失败，请稍后重试":            "容量チェックに失敗しました。後でもう一度お試しください",
+	"附件超出配额限制。已用 %s / 总配额 %s": "添付ファイルが容量を超えています。使用 %s / 合計 %s",
+	"外部投递未启用":                 "外部送信は有効ではありません",
+	"外部收件人过多：最多 %d 个":         "外部宛先が多すぎます：最大 %d 件",
+	"外发邮件入队失败 (%s): %v":       "外部メールのキュー登録に失敗しました (%s): %v",
+	"投递邮件失败: %v":              "メールの配信に失敗しました: %v",
+	"保存邮件失败: %v":              "メールの保存に失敗しました: %v",
+	"当前密码不正确":                 "現在のパスワードが正しくありません",
+	"新密码不能为空":                 "新しいパスワードは必須です",
+	"两次输入的密码不一致":              "パスワードが一致しません",
+	"密码加密失败":                  "パスワードの暗号化に失敗しました",
+	"密码更新失败":                  "パスワードの更新に失敗しました",
+	"密码修改成功":                  "パスワードを変更しました",
+	"邮箱不存在":                   "メールボックスが存在しません",
+	"加载邮件列表失败: %v":            "メール一覧の読み込みに失敗しました: %v",
+	"无效的邮件ID":                 "無効なメール ID",
+	"邮件不存在":                   "メールが存在しません",
+	"禁止访问":                    "アクセスが拒否されました",
+	"无效的附件ID":                 "無効な添付ファイル ID",
+	"附件不存在":                   "添付ファイルが存在しません",
+	"读取附件失败":                  "添付ファイルの読み込みに失敗しました",
+	"删除失败":                    "削除に失敗しました",
+	"恢复失败":                    "復元に失敗しました",
+	"清空文件夹失败: %v":             "フォルダを空にできませんでした: %v",
+
+	// ---------- 管理操作错误（admin.go） ----------
+	"无效的连接ID":       "無効な接続 ID",
+	"连接不存在或已断开":     "接続が存在しないか切断されています",
+	"管理员手动封禁（连接断开）": "管理者による手動ブロック（接続切断）",
+	"封禁失败: %v":      "ブロックに失敗しました: %v",
+	"加载域名列表失败: %v":  "ドメイン一覧の読み込みに失敗しました: %v",
+	"请输入域名":         "ドメイン名を入力してください",
+	"创建域名失败: %v":    "ドメインの作成に失敗しました: %v",
+	"无效的域名ID":       "無効なドメイン ID",
+	"域名不存在":         "ドメインが存在しません",
+	"✅ 已从 Caddy 获取证书并保存到域名 TLS 目录，同时已启用该域名的 TLS；证书已热加载，无需重启服务。": "✅ Caddy から証明書を取得し、ドメインの TLS ディレクトリに保存しました。TLS が有効になり、ホットリロード済みです。再起動は不要です。",
+	"启用 TLS 时必须填写 TLS 私钥和公钥证书": "TLS を有効にするには秘密鍵と証明書が必要です",
+	"TLS 私钥和公钥证书必须同时填写":        "秘密鍵と証明書は両方必要です",
+	"TLS 证书或私钥无效: %v":          "TLS 証明書または秘密鍵が無効です: %v",
+	"创建 TLS 证书目录失败: %v":        "TLS ディレクトリの作成に失敗しました: %v",
+	"保存 TLS 公钥证书失败: %v":        "TLS 証明書の保存に失敗しました: %v",
+	"保存 TLS 私钥失败: %v":          "TLS 秘密鍵の保存に失敗しました: %v",
+	"从 Caddy 获取证书失败: %v":       "Caddy からの証明書取得に失敗しました: %v",
+	"更新域名记录失败: %v":             "ドメイン情報の更新に失敗しました: %v",
+	"更新域名失败: %v":               "ドメインの更新に失敗しました: %v",
+	"删除域名失败: %v":               "ドメインの削除に失敗しました: %v",
+	"加载用户列表失败: %v":             "ユーザー一覧の読み込みに失敗しました: %v",
+	"请填写所有必填字段":                "必須項目をすべて入力してください",
+	"创建用户失败: %v":               "ユーザーの作成に失敗しました: %v",
+	"无效的用户ID":                  "無効なユーザー ID",
+	"不能删除自己的账户":                "自分のアカウントは削除できません",
+	"删除用户失败: %v":               "ユーザーの削除に失敗しました: %v",
+	"用户不存在":                    "ユーザーが存在しません",
+	"更新用户失败: %v":               "ユーザーの更新に失敗しました: %v",
+	"加载黑名单失败: %v":              "ブラックリストの読み込みに失敗しました: %v",
+	"无效的记录ID":                  "無効なレコード ID",
+	"解封失败: %v":                 "ブロック解除に失敗しました: %v",
+	"加载协议日志失败: %v":             "プロトコルログの読み込みに失敗しました: %v",
+	"加载外发队列失败: %v":             "送信キューの読み込みに失敗しました: %v",
+	"外发服务不可用":                  "送信サービスを利用できません",
+	"重试失败: %v":                 "再試行に失敗しました: %v",
+	"取消失败: %v":                 "キャンセルに失敗しました: %v",
+	"无效的队列ID":                  "無効なキュー ID",
+	"禁止访问：需要管理员权限":             "アクセスが拒否されました：管理者権限が必要です",
+}

internal/i18n/i18n.go

@@ -0,0 +1,139 @@
+// Package i18n provides lightweight UI localization for the MailGo web
+// frontend. Supported languages: zh (Chinese), en (English, fallback) and
+// ja (Japanese). Users may also pick "auto" so the effective language is
+// derived from their browser's Accept-Language header.
+//
+// Translation keys are the original Chinese UI strings themselves: the zh
+// catalog is the identity map, and the en/ja catalogs map those keys to
+// their translations. Missing translations fall back to English, then to
+// the key itself.
+package i18n
+
+import (
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// Language preference values stored on the user record.
+const (
+	// LangAuto 跟随浏览器语言（Accept-Language）。
+	LangAuto = "auto"
+	// LangEn 英语：兜底语言。
+	LangEn = "en"
+	// LangZh 中文。
+	LangZh = "zh"
+	// LangJa 日文。
+	LangJa = "ja"
+)
+
+// Supported 判断 lang 是否为可显式选择的界面语言（不含 auto）。
+func Supported(lang string) bool {
+	switch lang {
+	case LangEn, LangZh, LangJa:
+		return true
+	default:
+		return false
+	}
+}
+
+// Normalize 把浏览器语言标签规整为受支持的语言代码：
+// zh-CN / zh-TW / zh-Hans → zh；ja-JP → ja；en-US / en-GB → en；
+// 其余返回空串（无法识别）。
+func Normalize(tag string) string {
+	tag = strings.ToLower(strings.TrimSpace(tag))
+	if i := strings.IndexByte(tag, '-'); i >= 0 {
+		tag = tag[:i]
+	}
+	if i := strings.IndexByte(tag, '_'); i >= 0 {
+		tag = tag[:i]
+	}
+	switch tag {
+	case LangZh, "zh-hans", "zh-hant":
+		return LangZh
+	case LangJa:
+		return LangJa
+	case LangEn:
+		return LangEn
+	default:
+		return ""
+	}
+}
+
+// FromAcceptLanguage 从 Accept-Language 请求头解析首选语言。
+// 按 q 值（缺省 1.0）降序取第一个受支持的语言；都不支持时回退英语。
+func FromAcceptLanguage(header string) string {
+	type entry struct {
+		lang string
+		q    float64
+	}
+	var entries []entry
+	for _, part := range strings.Split(header, ",") {
+		part = strings.TrimSpace(part)
+		if part == "" {
+			continue
+		}
+		tag := part
+		q := 1.0
+		if i := strings.IndexByte(part, ';'); i >= 0 {
+			tag = strings.TrimSpace(part[:i])
+			for _, param := range strings.Split(part[i+1:], ";") {
+				param = strings.TrimSpace(param)
+				if strings.HasPrefix(param, "q=") {
+					if v, err := strconv.ParseFloat(param[2:], 64); err == nil {
+						q = v
+					}
+				}
+			}
+		}
+		if lang := Normalize(tag); lang != "" {
+			entries = append(entries, entry{lang: lang, q: q})
+		}
+	}
+	sort.SliceStable(entries, func(i, j int) bool { return entries[i].q > entries[j].q })
+	for _, e := range entries {
+		if e.q > 0 {
+			return e.lang
+		}
+	}
+	return LangEn
+}
+
+// Resolve 计算有效界面语言：用户偏好为显式语言时直接采用；
+// auto（或空/未知值）时按浏览器 Accept-Language 解析；最终兜底英语。
+func Resolve(pref, acceptLanguage string) string {
+	if Supported(pref) {
+		return pref
+	}
+	return FromAcceptLanguage(acceptLanguage)
+}
+
+// T 返回 key 在 lang 下的译文。zh 直接返回 key；
+// ja 优先查日文表，缺译回退英文表；其余语言（含未知）查英文表，
+// 仍缺失时原样返回 key（保证界面永不出现空文本）。
+func T(lang, key string) string {
+	switch Normalize(lang) {
+	case LangZh:
+		return key
+	case LangJa:
+		if s, ok := ja[key]; ok {
+			return s
+		}
+		if s, ok := en[key]; ok {
+			return s
+		}
+		return key
+	default:
+		if s, ok := en[key]; ok {
+			return s
+		}
+		return key
+	}
+}
+
+// TF 是 T 的格式化版本：对译文执行 fmt.Sprintf。
+// 用于带占位符的消息（如「还剩 %d 次尝试机会」）。
+func TF(lang, key string, args ...interface{}) string {
+	return fmt.Sprintf(T(lang, key), args...)
+}

internal/i18n/i18n_test.go

@@ -0,0 +1,114 @@
+package i18n
+
+import "testing"
+
+func TestNormalize(t *testing.T) {
+	cases := map[string]string{
+		"zh":      "zh",
+		"zh-CN":   "zh",
+		"zh-TW":   "zh",
+		"zh-Hans": "zh",
+		"ja":      "ja",
+		"ja-JP":   "ja",
+		"en":      "en",
+		"en-US":   "en",
+		"en_GB":   "en",
+		"fr":      "",
+		"":        "",
+	}
+	for in, want := range cases {
+		if got := Normalize(in); got != want {
+			t.Errorf("Normalize(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
+
+func TestFromAcceptLanguage(t *testing.T) {
+	cases := []struct {
+		header string
+		want   string
+	}{
+		{"zh-CN,zh;q=0.9,en;q=0.8", "zh"},
+		{"ja-JP,ja;q=0.9,en;q=0.8", "ja"},
+		{"en-US,en;q=0.9", "en"},
+		{"en;q=0.5,zh;q=0.9", "zh"}, // q 值优先
+		{"fr-FR,de-DE", "en"},       // 全部不支持 → 兜底英语
+		{"", "en"},
+	}
+	for _, tc := range cases {
+		if got := FromAcceptLanguage(tc.header); got != tc.want {
+			t.Errorf("FromAcceptLanguage(%q) = %q, want %q", tc.header, got, tc.want)
+		}
+	}
+}
+
+func TestResolve(t *testing.T) {
+	cases := []struct {
+		pref, header, want string
+	}{
+		{"auto", "ja-JP,ja;q=0.9,en;q=0.8", "ja"},
+		{"auto", "en-US,en;q=0.9", "en"},
+		{"auto", "fr-FR", "en"},
+		{"zh", "en-US,en;q=0.9", "zh"}, // 显式偏好优先于浏览器
+		{"ja", "en-US", "ja"},
+		{"en", "zh-CN,zh;q=0.9", "en"},
+		{"", "zh-CN", "zh"},
+		{"fr", "zh-CN", "zh"}, // 非法偏好按 auto 处理
+	}
+	for _, tc := range cases {
+		if got := Resolve(tc.pref, tc.header); got != tc.want {
+			t.Errorf("Resolve(%q, %q) = %q, want %q", tc.pref, tc.header, got, tc.want)
+		}
+	}
+}
+
+func TestT(t *testing.T) {
+	key := "收件箱"
+	// zh 恒等于 key 本身
+	if got := T("zh", key); got != key {
+		t.Errorf("T(zh) = %q, want %q", got, key)
+	}
+	// en
+	if got, want := T("en", key), "Inbox"; got != want {
+		t.Errorf("T(en) = %q, want %q", got, want)
+	}
+	// ja
+	if got, want := T("ja", key), "受信トレイ"; got != want {
+		t.Errorf("T(ja) = %q, want %q", got, want)
+	}
+	// 未知语言 → 英文兜底
+	if got := T("fr", key); got != "Inbox" {
+		t.Errorf("T(fr) = %q, want Inbox", got)
+	}
+	// 无此键 → 原样返回 key
+	if got := T("en", "不存在的键"); got != "不存在的键" {
+		t.Errorf("T(missing) = %q, want key itself", got)
+	}
+}
+
+func TestTF(t *testing.T) {
+	key := "用户名或密码错误，还剩 %d 次尝试机会"
+	if got, want := TF("zh", key, 3), "用户名或密码错误，还剩 3 次尝试机会"; got != want {
+		t.Errorf("TF(zh) = %q, want %q", got, want)
+	}
+	if got, want := TF("en", key, 2), "Incorrect username or password. 2 attempts remaining"; got != want {
+		t.Errorf("TF(en) = %q, want %q", got, want)
+	}
+	if got, want := TF("ja", key, 1), "ユーザー名またはパスワードが違います。あと 1 回試行できます"; got != want {
+		t.Errorf("TF(ja) = %q, want %q", got, want)
+	}
+}
+
+// TestCatalogCoverage 校验 en/ja 目录中不包含空译文。
+func TestCatalogCoverage(t *testing.T) {
+	for k, v := range en {
+		if v == "" {
+			t.Errorf("en 目录空译文: %q", k)
+		}
+	}
+	for k, v := range ja {
+		if v == "" {
+			t.Errorf("ja 目录空译文: %q", k)
+		}
+	}
+}

internal/store/user_store.go

@@ -30,6 +30,8 @@ type UserStore interface {
 	ListAll(page, size int) ([]db.User, int64, error)
 	UpdateUsedBytes(id uint, delta int64) error
 	UpdatePassword(userID uint, hashedPassword string) error
+	// UpdateLanguage 更新用户界面语言偏好（auto | en | zh | ja）。
+	UpdateLanguage(userID uint, lang string) error
 	// TryReserveQuota 原子预扣 delta 字节：仅在不超过配额时生效并返回 true，
 	// 否则不做任何修改返回 false。防止并发提交绕过配额检查（TOCTOU）。
 	TryReserveQuota(userID uint, delta int64) (bool, error)
@@ -209,6 +211,17 @@ func (s *userStoreGorm) UpdatePassword(userID uint, hashedPassword string) error
 		}).Error
 }
 
+// UpdateLanguage 更新用户界面语言偏好。非法值（非 auto/en/zh/ja）回退 auto。
+func (s *userStoreGorm) UpdateLanguage(userID uint, lang string) error {
+	switch lang {
+	case "auto", "en", "zh", "ja":
+	default:
+		lang = "auto"
+	}
+	return s.db.Model(&db.User{}).Where("id = ?", userID).
+		Update("language", lang).Error
+}
+
 // ListAll retrieves a paginated list of all users across all domains.
 func (s *userStoreGorm) ListAll(page, size int) ([]db.User, int64, error) {
 	var users []db.User

internal/web/handlers/admin.go

@@ -16,6 +16,7 @@ import (
 	"mail_go/internal/connhub"
 	"mail_go/internal/db"
 	"mail_go/internal/dkim"
+	"mail_go/internal/i18n"
 	"mail_go/internal/outbound"
 	"mail_go/internal/storage"
 	"mail_go/internal/store"
@@ -69,13 +70,13 @@ const manualBanDuration = 180 * 24 * time.Hour
 func (h *AdminHandler) DisconnectConnection(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的连接ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的连接ID"))
 		return
 	}
 
 	conn, ok := h.hub.Get(id)
 	if !ok {
-		c.String(http.StatusNotFound, "连接不存在或已断开")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "连接不存在或已断开"))
 		return
 	}
 
@@ -83,7 +84,7 @@ func (h *AdminHandler) DisconnectConnection(c *gin.Context) {
 	// BanIP 为 upsert 语义：清理该 IP 既有观察/重复记录后仅保留一条，
 	// 避免与阶段性封禁的计数/档位记录错位。
 	if err := h.stores.Bans.BanIP(conn.IP, "管理员手动封禁（连接断开）", manualBanDuration); err != nil {
-		c.String(http.StatusInternalServerError, "封禁失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "封禁失败: %v", err))
 		return
 	}
 
@@ -105,7 +106,7 @@ func (h *AdminHandler) ListConnections(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_connections", gin.H{
+	c.HTML(200, "admin_connections", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"conns":        conns,
 		"total":        total,
@@ -114,7 +115,7 @@ func (h *AdminHandler) ListConnections(c *gin.Context) {
 		"pop3Count":    pop3Count,
 		"now":          time.Now(),
 		"activeFolder": "connections",
-	})
+	}))
 }
 
 // Dashboard renders the admin dashboard with summary statistics.
@@ -153,7 +154,7 @@ func (h *AdminHandler) Dashboard(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_dashboard", gin.H{
+	c.HTML(200, "admin_dashboard", withLang(c, gin.H{
 		"currentUser":   currentUser,
 		"domainCount":   domainCount,
 		"userCount":     userCount,
@@ -171,7 +172,7 @@ func (h *AdminHandler) Dashboard(c *gin.Context) {
 		"weekSent":      weekSent,
 		"banCount":      banCount,
 		"activeFolder":  "admin",
-	})
+	}))
 }
 
 // ListDomains renders the domain list page.
@@ -179,7 +180,7 @@ func (h *AdminHandler) ListDomains(c *gin.Context) {
 	page := getPageParam(c, "page", 1)
 	domains, total, err := h.stores.Domains.List(page, 20)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载域名列表失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载域名列表失败: %v", err))
 		return
 	}
 
@@ -193,7 +194,7 @@ func (h *AdminHandler) ListDomains(c *gin.Context) {
 		totalPages = 0
 	}
 
-	c.HTML(200, "admin_domains", gin.H{
+	c.HTML(200, "admin_domains", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"domains":      domains,
 		"total":        total,
@@ -201,20 +202,20 @@ func (h *AdminHandler) ListDomains(c *gin.Context) {
 		"pageSize":     20,
 		"totalPages":   totalPages,
 		"activeFolder": "domains",
-	})
+	}))
 }
 
 // NewDomain renders the new domain form page.
 func (h *AdminHandler) NewDomain(c *gin.Context) {
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_domain_form", gin.H{
+	c.HTML(200, "admin_domain_form", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "domains",
 		"error":        "",
 		"isEdit":       false,
 		"domain":       &db.Domain{},
-	})
+	}))
 }
 
 // CreateDomain processes the new domain form submission.
@@ -227,10 +228,10 @@ func (h *AdminHandler) CreateDomain(c *gin.Context) {
 
 	if name == "" {
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusBadRequest, "admin_domain_form", gin.H{
+		c.HTML(http.StatusBadRequest, "admin_domain_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "domains",
-			"error":        "请输入域名",
+			"error":        i18n.T(langOf(c), "请输入域名"),
 			"isEdit":       false,
 			"domain": &db.Domain{
 				Name:       name,
@@ -239,7 +240,7 @@ func (h *AdminHandler) CreateDomain(c *gin.Context) {
 				Pop3Port:   pop3Port,
 				TlsEnabled: tlsEnabled,
 			},
-		})
+		}))
 		return
 	}
 
@@ -263,13 +264,13 @@ func (h *AdminHandler) CreateDomain(c *gin.Context) {
 
 	if err := h.stores.Domains.Create(domain); err != nil {
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusBadRequest, "admin_domain_form", gin.H{
+		c.HTML(http.StatusBadRequest, "admin_domain_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "domains",
-			"error":        fmt.Sprintf("创建域名失败: %v", err),
+			"error":        i18n.TF(langOf(c), "创建域名失败: %v", err),
 			"isEdit":       false,
 			"domain":       domain,
-		})
+		}))
 		return
 	}
 
@@ -280,13 +281,13 @@ func (h *AdminHandler) CreateDomain(c *gin.Context) {
 func (h *AdminHandler) EditDomain(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的域名ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的域名ID"))
 		return
 	}
 
 	domain, err := h.stores.Domains.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "域名不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "域名不存在"))
 		return
 	}
 
@@ -297,11 +298,11 @@ func (h *AdminHandler) EditDomain(c *gin.Context) {
 		caddyMsg = c.Query("caddy_err")
 		caddyMsgType = "error"
 	} else if c.Query("caddy_ok") == "1" {
-		caddyMsg = "✅ 已从 Caddy 获取证书并保存到域名 TLS 目录，同时已启用该域名的 TLS；证书已热加载，无需重启服务。"
+		caddyMsg = i18n.T(langOf(c), "✅ 已从 Caddy 获取证书并保存到域名 TLS 目录，同时已启用该域名的 TLS；证书已热加载，无需重启服务。")
 		caddyMsgType = "success"
 	}
 
-	c.HTML(200, "admin_domain_form", gin.H{
+	c.HTML(200, "admin_domain_form", withLang(c, gin.H{
 		"currentUser":       currentUser,
 		"activeFolder":      "domains",
 		"error":             "",
@@ -311,20 +312,20 @@ func (h *AdminHandler) EditDomain(c *gin.Context) {
 		"tlsCertConfigured": domain.TlsCertPath != "" && domain.TlsKeyPath != "",
 		"caddyMsg":          caddyMsg,
 		"caddyMsgType":      caddyMsgType,
-	})
+	}))
 }
 
 // UpdateDomain 处理编辑域名表单提交
 func (h *AdminHandler) UpdateDomain(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的域名ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的域名ID"))
 		return
 	}
 
 	domain, err := h.stores.Domains.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "域名不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "域名不存在"))
 		return
 	}
 
@@ -335,7 +336,7 @@ func (h *AdminHandler) UpdateDomain(c *gin.Context) {
 
 	tlsPrivateKey := strings.TrimSpace(c.PostForm("tls_private_key"))
 	tlsPublicCert := strings.TrimSpace(c.PostForm("tls_public_cert"))
-	if err := h.handleDomainTLSUpdate(domain, tlsPublicCert, tlsPrivateKey); err != nil {
+	if err := h.handleDomainTLSUpdate(langOf(c), domain, tlsPublicCert, tlsPrivateKey); err != nil {
 		h.renderDomainFormError(c, domain, err.Error(), tlsPublicCert)
 		return
 	}
@@ -351,7 +352,7 @@ func (h *AdminHandler) UpdateDomain(c *gin.Context) {
 	}
 
 	if err := h.stores.Domains.Update(domain); err != nil {
-		h.renderDomainFormError(c, domain, fmt.Sprintf("更新域名失败: %v", err), tlsPublicCert)
+		h.renderDomainFormError(c, domain, i18n.TF(langOf(c), "更新域名失败: %v", err), tlsPublicCert)
 		return
 	}
 
@@ -364,43 +365,45 @@ func (h *AdminHandler) UpdateDomain(c *gin.Context) {
 func (h *AdminHandler) FetchCaddyCert(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的域名ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的域名ID"))
 		return
 	}
 
 	domain, err := h.stores.Domains.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "域名不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "域名不存在"))
 		return
 	}
 
+	lang := langOf(c)
 	editURL := fmt.Sprintf("/admin/domains/%d/edit", domain.ID)
-	fail := func(msg string) {
+	fail := func(key string, args ...interface{}) {
+		msg := i18n.TF(lang, key, args...)
 		log.Printf("从 Caddy 获取证书失败 domain=%s: %s", domain.Name, msg)
 		c.Redirect(http.StatusFound, editURL+"?caddy_err="+url.QueryEscape(msg))
 	}
 
 	cert, err := caddycert.Fetch(domain.Name, h.caddyCertRoots())
 	if err != nil {
-		fail(fmt.Sprintf("从 Caddy 获取证书失败: %v", err))
+		fail("从 Caddy 获取证书失败: %v", err)
 		return
 	}
 
 	// 保存到域名 TLS 目录（与手动上传证书的位置一致）
 	domainTLSDir := filepath.Join(h.tlsDir, strconv.FormatUint(uint64(domain.ID), 10))
 	if err := os.MkdirAll(domainTLSDir, 0700); err != nil {
-		fail(fmt.Sprintf("创建 TLS 证书目录失败: %v", err))
+		fail("创建 TLS 证书目录失败: %v", err)
 		return
 	}
 
 	certPath := filepath.Join(domainTLSDir, "cert.pem")
 	keyPath := filepath.Join(domainTLSDir, "key.pem")
 	if err := os.WriteFile(certPath, cert.CertPEM, 0644); err != nil {
-		fail(fmt.Sprintf("保存 TLS 公钥证书失败: %v", err))
+		fail("保存 TLS 公钥证书失败: %v", err)
 		return
 	}
 	if err := os.WriteFile(keyPath, cert.KeyPEM, 0600); err != nil {
-		fail(fmt.Sprintf("保存 TLS 私钥失败: %v", err))
+		fail("保存 TLS 私钥失败: %v", err)
 		return
 	}
 
@@ -408,7 +411,7 @@ func (h *AdminHandler) FetchCaddyCert(c *gin.Context) {
 	domain.TlsKeyPath = keyPath
 	domain.TlsEnabled = true
 	if err := h.stores.Domains.Update(domain); err != nil {
-		fail(fmt.Sprintf("更新域名记录失败: %v", err))
+		fail("更新域名记录失败: %v", err)
 		return
 	}
 
@@ -451,7 +454,7 @@ func normalizePEM(s string) string {
 	return s
 }
 
-func (h *AdminHandler) handleDomainTLSUpdate(domain *db.Domain, publicCert, privateKey string) error {
+func (h *AdminHandler) handleDomainTLSUpdate(lang string, domain *db.Domain, publicCert, privateKey string) error {
 	// 归一化换行，保证与磁盘文件一致，避免表单往返时被误判为已修改
 	publicCert = normalizePEM(strings.TrimSpace(publicCert))
 	privateKey = normalizePEM(strings.TrimSpace(privateKey))
@@ -465,31 +468,31 @@ func (h *AdminHandler) handleDomainTLSUpdate(domain *db.Domain, publicCert, priv
 		if hasExistingCert {
 			return nil
 		}
-		return fmt.Errorf("启用 TLS 时必须填写 TLS 私钥和公钥证书")
+		return fmt.Errorf("%s", i18n.T(lang, "启用 TLS 时必须填写 TLS 私钥和公钥证书"))
 	}
 	if hasExistingCert && privateKey == "" && normalizePEM(strings.TrimSpace(readTLSCert(domain.TlsCertPath))) == publicCert {
 		return nil
 	}
 	if publicCert == "" || privateKey == "" {
-		return fmt.Errorf("TLS 私钥和公钥证书必须同时填写")
+		return fmt.Errorf("%s", i18n.T(lang, "TLS 私钥和公钥证书必须同时填写"))
 	}
 
 	if _, err := tls.X509KeyPair([]byte(publicCert), []byte(privateKey)); err != nil {
-		return fmt.Errorf("TLS 证书或私钥无效: %v", err)
+		return fmt.Errorf("%s", i18n.TF(lang, "TLS 证书或私钥无效: %v", err))
 	}
 
 	domainTLSDir := filepath.Join(h.tlsDir, strconv.FormatUint(uint64(domain.ID), 10))
 	if err := os.MkdirAll(domainTLSDir, 0700); err != nil {
-		return fmt.Errorf("创建 TLS 证书目录失败: %v", err)
+		return fmt.Errorf("%s", i18n.TF(lang, "创建 TLS 证书目录失败: %v", err))
 	}
 
 	certPath := filepath.Join(domainTLSDir, "cert.pem")
 	keyPath := filepath.Join(domainTLSDir, "key.pem")
 	if err := os.WriteFile(certPath, []byte(publicCert+"\n"), 0644); err != nil {
-		return fmt.Errorf("保存 TLS 公钥证书失败: %v", err)
+		return fmt.Errorf("%s", i18n.TF(lang, "保存 TLS 公钥证书失败: %v", err))
 	}
 	if err := os.WriteFile(keyPath, []byte(privateKey+"\n"), 0600); err != nil {
-		return fmt.Errorf("保存 TLS 私钥失败: %v", err)
+		return fmt.Errorf("%s", i18n.TF(lang, "保存 TLS 私钥失败: %v", err))
 	}
 
 	domain.TlsCertPath = certPath
@@ -503,7 +506,7 @@ func (h *AdminHandler) renderDomainFormError(c *gin.Context, domain *db.Domain,
 		tlsPublicCert = readTLSCert(domain.TlsCertPath)
 	}
 
-	c.HTML(http.StatusBadRequest, "admin_domain_form", gin.H{
+	c.HTML(http.StatusBadRequest, "admin_domain_form", withLang(c, gin.H{
 		"currentUser":       currentUser,
 		"activeFolder":      "domains",
 		"error":             message,
@@ -511,19 +514,19 @@ func (h *AdminHandler) renderDomainFormError(c *gin.Context, domain *db.Domain,
 		"domain":            domain,
 		"tlsPublicCert":     tlsPublicCert,
 		"tlsCertConfigured": domain.TlsCertPath != "" && domain.TlsKeyPath != "",
-	})
+	}))
 }
 
 // DeleteDomain removes a domain by ID.
 func (h *AdminHandler) DeleteDomain(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的域名ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的域名ID"))
 		return
 	}
 
 	if err := h.stores.Domains.Delete(uint(id)); err != nil {
-		c.String(http.StatusInternalServerError, "删除域名失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "删除域名失败: %v", err))
 		return
 	}
 
@@ -534,24 +537,24 @@ func (h *AdminHandler) DeleteDomain(c *gin.Context) {
 func (h *AdminHandler) DNSHint(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的域名ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的域名ID"))
 		return
 	}
 
 	domain, err := h.stores.Domains.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "域名不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "域名不存在"))
 		return
 	}
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_dns_hint", gin.H{
+	c.HTML(200, "admin_dns_hint", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "domains",
 		"domain":       domain,
 		"dkimRecord":   dkim.GetDKIMDNSRecord(domain.DkimPublicKey),
-	})
+	}))
 }
 
 // ListUsers renders the user list page.
@@ -560,7 +563,7 @@ func (h *AdminHandler) ListUsers(c *gin.Context) {
 
 	users, total, err := h.stores.Users.ListAll(page, 20)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载用户列表失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载用户列表失败: %v", err))
 		return
 	}
 
@@ -577,7 +580,7 @@ func (h *AdminHandler) ListUsers(c *gin.Context) {
 		totalPages = 0
 	}
 
-	c.HTML(200, "admin_users", gin.H{
+	c.HTML(200, "admin_users", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"users":        users,
 		"domains":      domains,
@@ -586,7 +589,7 @@ func (h *AdminHandler) ListUsers(c *gin.Context) {
 		"pageSize":     20,
 		"totalPages":   totalPages,
 		"activeFolder": "users",
-	})
+	}))
 }
 
 // NewUser renders the new user form page.
@@ -595,14 +598,14 @@ func (h *AdminHandler) NewUser(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_user_form", gin.H{
+	c.HTML(200, "admin_user_form", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "users",
 		"error":        "",
 		"isEdit":       false,
 		"domains":      domains,
 		"user":         &db.User{},
-	})
+	}))
 }
 
 // CreateUser processes the new user form submission.
@@ -616,10 +619,10 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 	if username == "" || password == "" || domainID == 0 {
 		domains, _, _ := h.stores.Domains.List(1, 1000)
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusBadRequest, "admin_user_form", gin.H{
+		c.HTML(http.StatusBadRequest, "admin_user_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "users",
-			"error":        "请填写所有必填字段",
+			"error":        i18n.T(langOf(c), "请填写所有必填字段"),
 			"isEdit":       false,
 			"domains":      domains,
 			"user": &db.User{
@@ -627,7 +630,7 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 				DomainID: domainID,
 				IsAdmin:  isAdmin,
 			},
-		})
+		}))
 		return
 	}
 
@@ -636,10 +639,10 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 	if err != nil {
 		domains, _, _ := h.stores.Domains.List(1, 1000)
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusInternalServerError, "admin_user_form", gin.H{
+		c.HTML(http.StatusInternalServerError, "admin_user_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "users",
-			"error":        "密码加密失败",
+			"error":        i18n.T(langOf(c), "密码加密失败"),
 			"isEdit":       false,
 			"domains":      domains,
 			"user": &db.User{
@@ -647,7 +650,7 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 				DomainID: domainID,
 				IsAdmin:  isAdmin,
 			},
-		})
+		}))
 		return
 	}
 
@@ -661,19 +664,20 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 		UsedBytes:    0,
 		IsActive:     true,
 		IsAdmin:      isAdmin,
+		Language:     normLang(c.PostForm("language")),
 	}
 
 	if err := h.stores.Users.Create(user); err != nil {
 		domains, _, _ := h.stores.Domains.List(1, 1000)
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusBadRequest, "admin_user_form", gin.H{
+		c.HTML(http.StatusBadRequest, "admin_user_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "users",
-			"error":        fmt.Sprintf("创建用户失败: %v", err),
+			"error":        i18n.TF(langOf(c), "创建用户失败: %v", err),
 			"isEdit":       false,
 			"domains":      domains,
 			"user":         user,
-		})
+		}))
 		return
 	}
 
@@ -684,18 +688,18 @@ func (h *AdminHandler) CreateUser(c *gin.Context) {
 func (h *AdminHandler) DeleteUser(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的用户ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的用户ID"))
 		return
 	}
 
 	currentUser, _ := c.Get("currentUser")
 	if currentUser.(*db.User).ID == uint(id) {
-		c.String(http.StatusBadRequest, "不能删除自己的账户")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "不能删除自己的账户"))
 		return
 	}
 
 	if err := h.stores.Users.Delete(uint(id)); err != nil {
-		c.String(http.StatusInternalServerError, "删除用户失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "删除用户失败: %v", err))
 		return
 	}
 
@@ -706,40 +710,40 @@ func (h *AdminHandler) DeleteUser(c *gin.Context) {
 func (h *AdminHandler) EditUser(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的用户ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的用户ID"))
 		return
 	}
 
 	user, err := h.stores.Users.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "用户不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "用户不存在"))
 		return
 	}
 
 	domains, _, _ := h.stores.Domains.List(1, 1000)
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_user_form", gin.H{
+	c.HTML(200, "admin_user_form", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "users",
 		"error":        "",
 		"isEdit":       true,
 		"domains":      domains,
 		"user":         user,
-	})
+	}))
 }
 
 // UpdateUser processes the edit user form submission.
 func (h *AdminHandler) UpdateUser(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的用户ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的用户ID"))
 		return
 	}
 
 	user, err := h.stores.Users.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "用户不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "用户不存在"))
 		return
 	}
 
@@ -757,6 +761,10 @@ func (h *AdminHandler) UpdateUser(c *gin.Context) {
 	user.QuotaBytes = int64(quotaGB) * 1024 * 1024 * 1024
 	user.IsActive = isActive
 	user.IsAdmin = isAdmin
+	// 界面语言偏好（表单未提交时保持原值）
+	if lang := c.PostForm("language"); lang != "" {
+		user.Language = normLang(lang)
+	}
 
 	// Update password only if a new one is provided
 	if password != "" {
@@ -764,14 +772,14 @@ func (h *AdminHandler) UpdateUser(c *gin.Context) {
 		if err != nil {
 			domains, _, _ := h.stores.Domains.List(1, 1000)
 			currentUser, _ := c.Get("currentUser")
-			c.HTML(http.StatusInternalServerError, "admin_user_form", gin.H{
+			c.HTML(http.StatusInternalServerError, "admin_user_form", withLang(c, gin.H{
 				"currentUser":  currentUser,
 				"activeFolder": "users",
-				"error":        "密码加密失败",
+				"error":        i18n.T(langOf(c), "密码加密失败"),
 				"isEdit":       true,
 				"domains":      domains,
 				"user":         user,
-			})
+			}))
 			return
 		}
 		user.PasswordHash = string(hashedPassword)
@@ -782,14 +790,14 @@ func (h *AdminHandler) UpdateUser(c *gin.Context) {
 	if err := h.stores.Users.Update(user); err != nil {
 		domains, _, _ := h.stores.Domains.List(1, 1000)
 		currentUser, _ := c.Get("currentUser")
-		c.HTML(http.StatusBadRequest, "admin_user_form", gin.H{
+		c.HTML(http.StatusBadRequest, "admin_user_form", withLang(c, gin.H{
 			"currentUser":  currentUser,
 			"activeFolder": "users",
-			"error":        fmt.Sprintf("更新用户失败: %v", err),
+			"error":        i18n.TF(langOf(c), "更新用户失败: %v", err),
 			"isEdit":       true,
 			"domains":      domains,
 			"user":         user,
-		})
+		}))
 		return
 	}
 
@@ -802,7 +810,7 @@ func (h *AdminHandler) ListBans(c *gin.Context) {
 
 	bans, total, err := h.stores.Bans.List(page, 20)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载黑名单失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载黑名单失败: %v", err))
 		return
 	}
 
@@ -823,7 +831,7 @@ func (h *AdminHandler) ListBans(c *gin.Context) {
 		totalPages = 0
 	}
 
-	c.HTML(200, "admin_bans", gin.H{
+	c.HTML(200, "admin_bans", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"rows":         rows,
 		"total":        total,
@@ -831,7 +839,7 @@ func (h *AdminHandler) ListBans(c *gin.Context) {
 		"pageSize":     20,
 		"totalPages":   totalPages,
 		"activeFolder": "bans",
-	})
+	}))
 }
 
 // banRow 是黑名单列表行：附带了当前是否封禁中的标记。
@@ -844,12 +852,12 @@ type banRow struct {
 func (h *AdminHandler) UnbanIP(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的记录ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的记录ID"))
 		return
 	}
 
 	if err := h.stores.Bans.Delete(uint(id)); err != nil {
-		c.String(http.StatusInternalServerError, "解封失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "解封失败: %v", err))
 		return
 	}
 
@@ -892,7 +900,7 @@ func (h *AdminHandler) ListProtocolLogs(c *gin.Context) {
 
 	logs, total, err := h.stores.ProtocolLogs.List(page, pageSize, filter)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载协议日志失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载协议日志失败: %v", err))
 		return
 	}
 
@@ -928,7 +936,7 @@ func (h *AdminHandler) ListProtocolLogs(c *gin.Context) {
 		"to":       url.QueryEscape(c.Query("to")),
 	}
 
-	c.HTML(200, "admin_protocol_logs", gin.H{
+	c.HTML(200, "admin_protocol_logs", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"logs":         logs,
 		"total":        total,
@@ -940,7 +948,7 @@ func (h *AdminHandler) ListProtocolLogs(c *gin.Context) {
 		"allStats":     normStats(allStats),
 		"keepDays":     h.protocolLogKeepDays,
 		"activeFolder": "protocol-logs",
-	})
+	}))
 }
 
 // CleanupProtocolLogs 手动清理超出保留天数的协议日志。
@@ -978,7 +986,7 @@ func (h *AdminHandler) ListMails(c *gin.Context) {
 	}
 
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载邮件列表失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载邮件列表失败: %v", err))
 		return
 	}
 
@@ -992,7 +1000,7 @@ func (h *AdminHandler) ListMails(c *gin.Context) {
 		totalPages = 0
 	}
 
-	c.HTML(200, "admin_mails", gin.H{
+	c.HTML(200, "admin_mails", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"messages":     messages,
 		"total":        total,
@@ -1001,20 +1009,20 @@ func (h *AdminHandler) ListMails(c *gin.Context) {
 		"totalPages":   totalPages,
 		"folder":       folder,
 		"activeFolder": "mails",
-	})
+	}))
 }
 
 // AdminViewMail renders the detail view of a specific mail for admin.
 func (h *AdminHandler) AdminViewMail(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "邮件不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "邮件不存在"))
 		return
 	}
 
@@ -1023,31 +1031,31 @@ func (h *AdminHandler) AdminViewMail(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_mail_view", gin.H{
+	c.HTML(200, "admin_mail_view", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"message":      msg,
 		"attachments":  attachments,
 		"activeFolder": "mails",
-	})
+	}))
 }
 
 // AdminDownloadAttachment serves an attachment file for admin (bypasses user ownership check).
 func (h *AdminHandler) AdminDownloadAttachment(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的附件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的附件ID"))
 		return
 	}
 
 	att, err := h.stores.Attachments.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "附件不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "附件不存在"))
 		return
 	}
 
 	data, err := h.storage.Read(att.FilePath)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "读取附件失败")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "读取附件失败"))
 		return
 	}
 
@@ -1062,7 +1070,7 @@ func (h *AdminHandler) ListOutbound(c *gin.Context) {
 
 	items, total, err := h.stores.Outbound.List(page, 20, status)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载外发队列失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载外发队列失败: %v", err))
 		return
 	}
 
@@ -1088,7 +1096,7 @@ func (h *AdminHandler) ListOutbound(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "admin_outbound", gin.H{
+	c.HTML(200, "admin_outbound", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"items":        items,
 		"total":        total,
@@ -1099,23 +1107,23 @@ func (h *AdminHandler) ListOutbound(c *gin.Context) {
 		"statCounts":   statCounts,
 		"statusText":   outbound.StatusText,
 		"activeFolder": "outbound",
-	})
+	}))
 }
 
 // RetryOutbound resets an outbound queue item for immediate redelivery.
 func (h *AdminHandler) RetryOutbound(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的队列ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的队列ID"))
 		return
 	}
 
 	if h.outbound == nil {
-		c.String(http.StatusInternalServerError, "外发服务不可用")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "外发服务不可用"))
 		return
 	}
 	if err := h.outbound.Retry(uint(id)); err != nil {
-		c.String(http.StatusInternalServerError, "重试失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "重试失败: %v", err))
 		return
 	}
 
@@ -1126,16 +1134,16 @@ func (h *AdminHandler) RetryOutbound(c *gin.Context) {
 func (h *AdminHandler) CancelOutbound(c *gin.Context) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的队列ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的队列ID"))
 		return
 	}
 
 	if h.outbound == nil {
-		c.String(http.StatusInternalServerError, "外发服务不可用")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "外发服务不可用"))
 		return
 	}
 	if err := h.outbound.Cancel(uint(id)); err != nil {
-		c.String(http.StatusInternalServerError, "取消失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "取消失败: %v", err))
 		return
 	}
 

internal/web/handlers/admin_tls_test.go

@@ -83,7 +83,7 @@ func TestHandleDomainTLSUpdateUnchangedCertCRLF(t *testing.T) {
 	domain := writeExistingCert(t, h.tlsDir, certLF, keyLF)
 
 	submittedCert := strings.ReplaceAll(certLF, "\n", "\r\n") // 模拟浏览器提交
-	if err := h.handleDomainTLSUpdate(domain, submittedCert, ""); err != nil {
+	if err := h.handleDomainTLSUpdate("zh", domain, submittedCert, ""); err != nil {
 		t.Fatalf("证书未修改且私钥留空时应保留现有私钥，实际报错: %v", err)
 	}
 }
@@ -95,7 +95,7 @@ func TestHandleDomainTLSUpdateNewPairCRLF(t *testing.T) {
 	h := &AdminHandler{tlsDir: t.TempDir()}
 	domain := &db.Domain{ID: 1, Name: "mail.example.com", TlsEnabled: true}
 
-	if err := h.handleDomainTLSUpdate(domain, certCRLF, keyCRLF); err != nil {
+	if err := h.handleDomainTLSUpdate("zh", domain, certCRLF, keyCRLF); err != nil {
 		t.Fatalf("CRLF 提交的新证书应保存成功，实际报错: %v", err)
 	}
 
@@ -119,7 +119,7 @@ func TestHandleDomainTLSUpdateChangedCertWithoutKey(t *testing.T) {
 	h := &AdminHandler{tlsDir: t.TempDir()}
 	domain := writeExistingCert(t, h.tlsDir, certA, keyA)
 
-	err := h.handleDomainTLSUpdate(domain, certB, "")
+	err := h.handleDomainTLSUpdate("zh", domain, certB, "")
 	if err == nil || !strings.Contains(err.Error(), "必须同时填写") {
 		t.Fatalf("修改证书但私钥留空应报“必须同时填写”，实际: %v", err)
 	}

internal/web/handlers/auth.go

@@ -11,6 +11,7 @@ import (
 
 	"mail_go/config"
 	"mail_go/internal/auth"
+	"mail_go/internal/i18n"
 	"mail_go/internal/store"
 
 	"github.com/gin-contrib/sessions"
@@ -37,12 +38,12 @@ func (h *AuthHandler) ShowLogin(c *gin.Context) {
 		c.Redirect(302, "/inbox")
 		return
 	}
-	c.HTML(200, "login", gin.H{
+	c.HTML(200, "login", withLang(c, gin.H{
 		"error":          "",
 		"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 		"ldapEnabled":    h.authCfg.LDAPEnabled,
 		"oauth2Provider": h.authCfg.OAuth2Provider,
-	})
+	}))
 }
 
 // DoLogin processes the login form submission.
@@ -54,7 +55,7 @@ func (h *AuthHandler) DoLogin(c *gin.Context) {
 	// Check if IP is banned
 	banned, entry := h.stores.Bans.IsBanned(ip)
 	if banned {
-		c.HTML(http.StatusForbidden, "banned", gin.H{"entry": entry})
+		c.HTML(http.StatusForbidden, "banned", withLang(c, gin.H{"entry": entry}))
 		return
 	}
 
@@ -62,12 +63,12 @@ func (h *AuthHandler) DoLogin(c *gin.Context) {
 	password := c.PostForm("password")
 
 	if email == "" || password == "" {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "请输入邮箱和密码",
+			"error":          i18n.T(langOf(c), "请输入邮箱和密码"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -79,17 +80,17 @@ func (h *AuthHandler) DoLogin(c *gin.Context) {
 		banned, failCount := h.stores.RecordAuthFailure(ip, h.banCfg.MaxFailAttempts, h.banCfg.BanDurationMin, "登录失败次数过多", knownUser)
 		if banned {
 			entry, _ := h.stores.Bans.GetByIP(ip)
-			c.HTML(http.StatusForbidden, "banned", gin.H{"entry": entry})
+			c.HTML(http.StatusForbidden, "banned", withLang(c, gin.H{"entry": entry}))
 			return
 		}
 
 		remaining := h.banCfg.MaxFailAttempts - failCount
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          fmt.Sprintf("用户名或密码错误，还剩 %d 次尝试机会", remaining),
+			"error":          i18n.TF(langOf(c), "用户名或密码错误，还剩 %d 次尝试机会", remaining),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -105,12 +106,12 @@ func (h *AuthHandler) DoLogin(c *gin.Context) {
 	session.Set("isAdmin", user.IsAdmin)
 	session.Set("loginAt", time.Now().Unix())
 	if err := session.Save(); err != nil {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "会话保存失败，请重试",
+			"error":          i18n.T(langOf(c), "会话保存失败，请重试"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -124,7 +125,7 @@ func (h *AuthHandler) LDAPLogin(c *gin.Context) {
 	// Check if IP is banned
 	banned, entry := h.stores.Bans.IsBanned(ip)
 	if banned {
-		c.HTML(http.StatusForbidden, "banned", gin.H{"entry": entry})
+		c.HTML(http.StatusForbidden, "banned", withLang(c, gin.H{"entry": entry}))
 		return
 	}
 
@@ -132,12 +133,12 @@ func (h *AuthHandler) LDAPLogin(c *gin.Context) {
 	password := c.PostForm("password")
 
 	if username == "" || password == "" {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "请输入LDAP用户名和密码",
+			"error":          i18n.T(langOf(c), "请输入LDAP用户名和密码"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -153,39 +154,39 @@ func (h *AuthHandler) LDAPLogin(c *gin.Context) {
 		banned, failCount := h.stores.RecordAuthFailure(ip, h.banCfg.MaxFailAttempts, h.banCfg.BanDurationMin, "LDAP 登录失败次数过多", true)
 		if banned {
 			entry, _ := h.stores.Bans.GetByIP(ip)
-			c.HTML(http.StatusForbidden, "banned", gin.H{"entry": entry})
+			c.HTML(http.StatusForbidden, "banned", withLang(c, gin.H{"entry": entry}))
 			return
 		}
 
 		remaining := h.banCfg.MaxFailAttempts - failCount
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          fmt.Sprintf("LDAP 认证失败，还剩 %d 次尝试机会", remaining),
+			"error":          i18n.TF(langOf(c), "LDAP 认证失败，还剩 %d 次尝试机会", remaining),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
 	// Look up or auto-create user by email
 	user, err := h.stores.Users.GetByEmail(email)
 	if err != nil {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "LDAP 账号未接入本系统，请联系管理员",
+			"error":          i18n.T(langOf(c), "LDAP 账号未接入本系统，请联系管理员"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
 	if !user.IsActive {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "用户已被禁用",
+			"error":          i18n.T(langOf(c), "用户已被禁用"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -201,12 +202,12 @@ func (h *AuthHandler) LDAPLogin(c *gin.Context) {
 	session.Set("isAdmin", user.IsAdmin)
 	session.Set("loginAt", time.Now().Unix())
 	if err := session.Save(); err != nil {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "会话保存失败，请重试",
+			"error":          i18n.T(langOf(c), "会话保存失败，请重试"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -246,7 +247,7 @@ func (h *AuthHandler) oauth2LoginVars() gin.H {
 // OAuth2Start redirects to the OAuth2 provider's authorization page.
 func (h *AuthHandler) OAuth2Start(c *gin.Context) {
 	if !h.authCfg.OAuth2Enabled {
-		c.String(http.StatusBadRequest, "OAuth2 未启用")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "OAuth2 未启用"))
 		return
 	}
 
@@ -254,7 +255,7 @@ func (h *AuthHandler) OAuth2Start(c *gin.Context) {
 	state, err := randomOAuth2State()
 	if err != nil {
 		log.Printf("生成 OAuth2 state 失败: %v", err)
-		c.String(http.StatusInternalServerError, "OAuth2 登录暂不可用，请稍后重试")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "OAuth2 登录暂不可用，请稍后重试"))
 		return
 	}
 	c.SetCookie(oauth2StateCookie, state, oauth2StateMaxAge, "/auth/oauth2", "", true, true)
@@ -264,7 +265,7 @@ func (h *AuthHandler) OAuth2Start(c *gin.Context) {
 // OAuth2Callback handles the OAuth2 provider's callback after user authorization.
 func (h *AuthHandler) OAuth2Callback(c *gin.Context) {
 	if !h.authCfg.OAuth2Enabled {
-		c.String(http.StatusBadRequest, "OAuth2 未启用")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "OAuth2 未启用"))
 		return
 	}
 
@@ -274,11 +275,11 @@ func (h *AuthHandler) OAuth2Callback(c *gin.Context) {
 	reqState := c.Query("state")
 	if cookieErr != nil || reqState == "" ||
 		subtle.ConstantTimeCompare([]byte(cookieState), []byte(reqState)) != 1 {
-		c.HTML(http.StatusForbidden, "login", func() gin.H {
+		c.HTML(http.StatusForbidden, "login", withLang(c, func() gin.H {
 			v := h.oauth2LoginVars()
-			v["error"] = "OAuth2 state 校验失败，请重新发起登录"
+			v["error"] = i18n.T(langOf(c), "OAuth2 state 校验失败，请重新发起登录")
 			return v
-		}())
+		}()))
 		return
 	}
 	// state 一次性使用：无论后续成败都立即失效
@@ -286,12 +287,12 @@ func (h *AuthHandler) OAuth2Callback(c *gin.Context) {
 
 	code := c.Query("code")
 	if code == "" {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "OAuth2 授权码缺失",
+			"error":          i18n.T(langOf(c), "OAuth2 授权码缺失"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -299,34 +300,34 @@ func (h *AuthHandler) OAuth2Callback(c *gin.Context) {
 	email, err := provider.HandleCallback(code)
 	if err != nil {
 		log.Printf("OAuth2 回调失败: %v", err)
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "OAuth2 认证失败，请重试或联系管理员",
+			"error":          i18n.T(langOf(c), "OAuth2 认证失败，请重试或联系管理员"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
 	// Look up user by email
 	user, err := h.stores.Users.GetByEmail(email)
 	if err != nil {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "OAuth2 账号未接入本系统，请联系管理员",
+			"error":          i18n.T(langOf(c), "OAuth2 账号未接入本系统，请联系管理员"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
 	if !user.IsActive {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "用户已被禁用",
+			"error":          i18n.T(langOf(c), "用户已被禁用"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 
@@ -339,12 +340,12 @@ func (h *AuthHandler) OAuth2Callback(c *gin.Context) {
 	session.Set("isAdmin", user.IsAdmin)
 	session.Set("loginAt", time.Now().Unix())
 	if err := session.Save(); err != nil {
-		c.HTML(200, "login", gin.H{
+		c.HTML(200, "login", withLang(c, gin.H{
-			"error":          "会话保存失败，请重试",
+			"error":          i18n.T(langOf(c), "会话保存失败，请重试"),
 			"oauth2Enabled":  h.authCfg.OAuth2Enabled,
 			"ldapEnabled":    h.authCfg.LDAPEnabled,
 			"oauth2Provider": h.authCfg.OAuth2Provider,
-		})
+		}))
 		return
 	}
 

internal/web/handlers/i18n.go

@@ -0,0 +1,39 @@
+package handlers
+
+import (
+	"mail_go/internal/i18n"
+
+	"github.com/gin-gonic/gin"
+)
+
+// langOf 返回当前请求的界面语言：优先取中间件解析好的 context 值
+// （登录用户偏好 / 浏览器语言），未设置时按浏览器 Accept-Language 兜底。
+func langOf(c *gin.Context) string {
+	if v, ok := c.Get("lang"); ok {
+		if s, ok := v.(string); ok && i18n.Supported(s) {
+			return s
+		}
+	}
+	return i18n.FromAcceptLanguage(c.GetHeader("Accept-Language"))
+}
+
+// withLang 把当前请求的界面语言注入模板数据（key "lang"），
+// 所有 c.HTML 渲染入口都应经过它，保证模板可调用 {{t .Lang "..."}}。
+func withLang(c *gin.Context, data gin.H) gin.H {
+	if data == nil {
+		data = gin.H{}
+	}
+	data["Lang"] = langOf(c)
+	return data
+}
+
+// normLang 把表单提交的语言偏好规整为合法值（auto | en | zh | ja），
+// 非法值回退 auto（跟随浏览器）。
+func normLang(v string) string {
+	switch v {
+	case i18n.LangAuto, i18n.LangEn, i18n.LangZh, i18n.LangJa:
+		return v
+	default:
+		return i18n.LangAuto
+	}
+}

internal/web/handlers/mail.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"mail_go/internal/db"
+	"mail_go/internal/i18n"
 	"mail_go/internal/imap_server"
 	"mail_go/internal/outbound"
 	"mail_go/internal/storage"
@@ -123,14 +124,14 @@ func (h *MailHandler) Folder(c *gin.Context) {
 	userID := c.GetUint("userID")
 	name, ok := h.svc.Canonical(userID, c.Param("name"))
 	if !ok {
-		c.String(http.StatusNotFound, "邮箱不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "邮箱不存在"))
 		return
 	}
 	page := getPageParam(c, "page", 1)
 
 	messages, total, err := h.svc.Messages(userID, name, page, 20)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "加载邮件列表失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "加载邮件列表失败: %v", err))
 		return
 	}
 
@@ -143,7 +144,7 @@ func (h *MailHandler) Folder(c *gin.Context) {
 	}
 
 	currentUser, _ := c.Get("currentUser")
-	c.HTML(200, "folder", gin.H{
+	c.HTML(200, "folder", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"messages":     messages,
 		"total":        total,
@@ -154,7 +155,7 @@ func (h *MailHandler) Folder(c *gin.Context) {
 		"activeFolder": name,
 		"isTrash":      name == "Trash",
 		"folders":      h.foldersFor(userID),
-	})
+	}))
 }
 
 // View renders the email detail page for a specific message.
@@ -162,19 +163,19 @@ func (h *MailHandler) View(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "邮件不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "邮件不存在"))
 		return
 	}
 
 	// Verify the message belongs to the current user
 	if msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 
@@ -191,14 +192,14 @@ func (h *MailHandler) View(c *gin.Context) {
 
 	currentUser, _ := c.Get("currentUser")
 
-	c.HTML(200, "view", gin.H{
+	c.HTML(200, "view", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"message":      msg,
 		"attachments":  attachments,
 		"activeFolder": msg.Folder,
 		"inTrash":      msg.Folder == "Trash",
 		"folders":      h.foldersFor(userID),
-	})
+	}))
 }
 
 // Compose renders the email composition page.
@@ -215,7 +216,7 @@ func (h *MailHandler) Compose(c *gin.Context) {
 		quotaBytes = user.QuotaBytes
 	}
 
-	c.HTML(200, "compose", gin.H{
+	c.HTML(200, "compose", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "compose",
 		"error":        "",
@@ -225,12 +226,12 @@ func (h *MailHandler) Compose(c *gin.Context) {
 		"usedBytes":    usedBytes,
 		"quotaBytes":   quotaBytes,
 		"folders":      h.foldersFor(userID),
-	})
+	}))
 }
 
 // composeData builds the shared template context for the compose page.
-func (h *MailHandler) composeData(userID uint, user *db.User, errMsg, to, subject, cc, body string) gin.H {
+func (h *MailHandler) composeData(c *gin.Context, userID uint, user *db.User, errMsg, to, subject, cc, body string) gin.H {
-	return gin.H{
+	return withLang(c, gin.H{
 		"currentUser":  user,
 		"activeFolder": "compose",
 		"error":        errMsg,
@@ -241,7 +242,7 @@ func (h *MailHandler) composeData(userID uint, user *db.User, errMsg, to, subjec
 		"usedBytes":    user.UsedBytes,
 		"quotaBytes":   user.QuotaBytes,
 		"folders":      h.foldersFor(userID),
-	}
+	})
 }
 
 // DoSend processes the email composition form, sends the email via SMTP,
@@ -258,7 +259,7 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 	cc := c.PostForm("cc")
 
 	if to == "" {
-		c.HTML(http.StatusBadRequest, "compose", h.composeData(userID, currentUser, "请输入收件人", to, subject, cc, htmlBody))
+		c.HTML(http.StatusBadRequest, "compose", h.composeData(c, userID, currentUser, i18n.T(langOf(c), "请输入收件人"), to, subject, cc, htmlBody))
 		return
 	}
 
@@ -276,7 +277,7 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 			}
 			reserved, err := h.stores.Users.TryReserveQuota(userID, totalNewSize)
 			if err != nil {
-				c.HTML(http.StatusInternalServerError, "compose", h.composeData(userID, currentUser, "配额检查失败，请稍后重试", to, subject, cc, htmlBody))
+				c.HTML(http.StatusInternalServerError, "compose", h.composeData(c, userID, currentUser, i18n.T(langOf(c), "配额检查失败，请稍后重试"), to, subject, cc, htmlBody))
 				return
 			}
 			if !reserved {
@@ -285,10 +286,10 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 				if user != nil {
 					usedBytes, quotaBytes = user.UsedBytes, user.QuotaBytes
 				}
-				c.HTML(http.StatusBadRequest, "compose", gin.H{
+				c.HTML(http.StatusBadRequest, "compose", withLang(c, gin.H{
 					"currentUser":  currentUser,
 					"activeFolder": "compose",
-					"error":        fmt.Sprintf("附件超出配额限制。已用 %s / 总配额 %s", formatBytes(usedBytes), formatBytes(quotaBytes)),
+					"error":        i18n.TF(langOf(c), "附件超出配额限制。已用 %s / 总配额 %s", formatBytes(usedBytes), formatBytes(quotaBytes)),
 					"to":           to,
 					"subject":      subject,
 					"cc":           cc,
@@ -296,7 +297,7 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 					"usedBytes":    usedBytes,
 					"quotaBytes":   quotaBytes,
 					"folders":      h.foldersFor(userID),
-				})
+				}))
 				return
 			}
 
@@ -355,16 +356,16 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 	if len(externalRecipients) > 0 {
 		ob := h.outbound
 		if ob == nil || !ob.Enabled() {
-			c.HTML(http.StatusBadRequest, "compose", h.composeData(userID, currentUser, "外部投递未启用", to, subject, cc, htmlBody))
+			c.HTML(http.StatusBadRequest, "compose", h.composeData(c, userID, currentUser, i18n.T(langOf(c), "外部投递未启用"), to, subject, cc, htmlBody))
 			return
 		}
 		if maxRcpt := ob.MaxRecipients(); maxRcpt > 0 && len(externalRecipients) > maxRcpt {
-			c.HTML(http.StatusBadRequest, "compose", h.composeData(userID, currentUser, fmt.Sprintf("外部收件人过多：最多 %d 个", maxRcpt), to, subject, cc, htmlBody))
+			c.HTML(http.StatusBadRequest, "compose", h.composeData(c, userID, currentUser, i18n.TF(langOf(c), "外部收件人过多：最多 %d 个", maxRcpt), to, subject, cc, htmlBody))
 			return
 		}
 		for _, rcpt := range externalRecipients {
 			if _, err := ob.Enqueue(currentUser, fromAddr, rcpt, []byte(rawMessage)); err != nil {
-				c.HTML(http.StatusBadRequest, "compose", h.composeData(userID, currentUser, fmt.Sprintf("外发邮件入队失败 (%s): %v", rcpt, err), to, subject, cc, htmlBody))
+				c.HTML(http.StatusBadRequest, "compose", h.composeData(c, userID, currentUser, i18n.TF(langOf(c), "外发邮件入队失败 (%s): %v", rcpt, err), to, subject, cc, htmlBody))
 				return
 			}
 		}
@@ -386,7 +387,7 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 			IsRead:    false,
 		}
 		if createErr := h.stores.Mails.Create(inboxMsg); createErr != nil {
-			c.HTML(http.StatusInternalServerError, "compose", h.composeData(userID, currentUser, fmt.Sprintf("投递邮件失败: %v", createErr), to, subject, cc, htmlBody))
+			c.HTML(http.StatusInternalServerError, "compose", h.composeData(c, userID, currentUser, i18n.TF(langOf(c), "投递邮件失败: %v", createErr), to, subject, cc, htmlBody))
 			return
 		}
 		// 本地投递成功 → IMAP 新邮件推送（IDLE 客户端实时收到通知）
@@ -412,7 +413,7 @@ func (h *MailHandler) DoSend(c *gin.Context) {
 	}
 
 	if createErr := h.stores.Mails.Create(msg); createErr != nil {
-		c.HTML(http.StatusInternalServerError, "compose", h.composeData(userID, currentUser, fmt.Sprintf("保存邮件失败: %v", createErr), to, subject, cc, htmlBody))
+		c.HTML(http.StatusInternalServerError, "compose", h.composeData(c, userID, currentUser, i18n.TF(langOf(c), "保存邮件失败: %v", createErr), to, subject, cc, htmlBody))
 		return
 	}
 
@@ -579,13 +580,13 @@ func (h *MailHandler) Delete(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil || msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 	userEmail := userEmailOf(c)
@@ -602,7 +603,7 @@ func (h *MailHandler) Delete(c *gin.Context) {
 		seq := h.seqOfFolder(userID, msg.Folder, msg.ID)
 		if err := h.svc.Move(userID, []uint{msg.ID}, "Trash"); err != nil {
 			log.Printf("web: 移入垃圾箱失败 msg=%d: %v", id, err)
-			c.String(http.StatusInternalServerError, "删除失败")
+			c.String(http.StatusInternalServerError, i18n.T(langOf(c), "删除失败"))
 			return
 		}
 		if h.pusher != nil && userEmail != "" {
@@ -624,13 +625,13 @@ func (h *MailHandler) Restore(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil || msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 	if msg.Folder != "Trash" {
@@ -641,7 +642,7 @@ func (h *MailHandler) Restore(c *gin.Context) {
 	seq := h.seqOfFolder(userID, "Trash", msg.ID)
 	if err := h.svc.Move(userID, []uint{msg.ID}, "INBOX"); err != nil {
 		log.Printf("web: 恢复邮件失败 msg=%d: %v", id, err)
-		c.String(http.StatusInternalServerError, "恢复失败")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "恢复失败"))
 		return
 	}
 	if h.pusher != nil {
@@ -658,13 +659,13 @@ func (h *MailHandler) Purge(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil || msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 
@@ -688,13 +689,13 @@ func (h *MailHandler) EmptyFolder(c *gin.Context) {
 	userID := c.GetUint("userID")
 	name, ok := h.svc.Canonical(userID, c.Param("name"))
 	if !ok {
-		c.String(http.StatusNotFound, "邮箱不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "邮箱不存在"))
 		return
 	}
 
 	msgs, err := h.stores.Mails.ListAllByUserAndFolder(userID, name)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "清空文件夹失败: %v", err)
+		c.String(http.StatusInternalServerError, i18n.TF(langOf(c), "清空文件夹失败: %v", err))
 		return
 	}
 	seqs := make([]uint32, 0, len(msgs))
@@ -715,13 +716,13 @@ func (h *MailHandler) MarkRead(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的邮件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的邮件ID"))
 		return
 	}
 
 	msg, err := h.stores.Mails.GetByID(uint(id))
 	if err != nil || msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 
@@ -752,26 +753,26 @@ func (h *MailHandler) DownloadAttachment(c *gin.Context) {
 	userID := c.GetUint("userID")
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
-		c.String(http.StatusBadRequest, "无效的附件ID")
+		c.String(http.StatusBadRequest, i18n.T(langOf(c), "无效的附件ID"))
 		return
 	}
 
 	att, err := h.stores.Attachments.GetByID(uint(id))
 	if err != nil {
-		c.String(http.StatusNotFound, "附件不存在")
+		c.String(http.StatusNotFound, i18n.T(langOf(c), "附件不存在"))
 		return
 	}
 
 	// Verify the message belongs to the current user
 	msg, err := h.stores.Mails.GetByID(att.MessageID)
 	if err != nil || msg.UserID != userID {
-		c.String(http.StatusForbidden, "禁止访问")
+		c.String(http.StatusForbidden, i18n.T(langOf(c), "禁止访问"))
 		return
 	}
 
 	data, err := h.storage.Read(att.FilePath)
 	if err != nil {
-		c.String(http.StatusInternalServerError, "读取附件失败")
+		c.String(http.StatusInternalServerError, i18n.T(langOf(c), "读取附件失败"))
 		return
 	}
 
@@ -797,65 +798,76 @@ func getPageParam(c *gin.Context, key string, defaultVal int) int {
 func (h *MailHandler) Settings(c *gin.Context) {
 	currentUser, _ := c.Get("currentUser")
 	userID := c.GetUint("userID")
-	c.HTML(200, "settings", gin.H{
+	c.HTML(200, "settings", withLang(c, gin.H{
 		"currentUser":  currentUser,
 		"activeFolder": "settings",
 		"error":        "",
 		"success":      "",
 		"mustChange":   c.Query("force") == "1",
 		"folders":      h.foldersFor(userID),
-	})
+	}))
 }
 
 // settingsData builds the shared template context for the settings page.
-func (h *MailHandler) settingsData(userID uint, user *db.User, errMsg, success string) gin.H {
+func (h *MailHandler) settingsData(c *gin.Context, userID uint, user *db.User, errMsg, success string) gin.H {
-	return gin.H{
+	return withLang(c, gin.H{
 		"currentUser":  user,
 		"activeFolder": "settings",
 		"error":        errMsg,
 		"success":      success,
 		"folders":      h.foldersFor(userID),
-	}
+	})
 }
 
-// UpdateSettings handles the password change form.
+// UpdateSettings 处理设置页表单：密码修改（old_password + new_password +
+// confirm_password）与界面语言偏好（仅 language 字段）二选一提交。
 func (h *MailHandler) UpdateSettings(c *gin.Context) {
 	userID := c.GetUint("userID")
 	currentUserVal, _ := c.Get("currentUser")
 	currentUser := currentUserVal.(*db.User)
 
+	// 仅提交 language 字段 → 语言偏好更新（设置页独立表单）
+	if lang := c.PostForm("language"); lang != "" && c.PostForm("old_password") == "" {
+		if err := h.stores.Users.UpdateLanguage(userID, lang); err != nil {
+			c.HTML(http.StatusInternalServerError, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "语言偏好保存失败"), ""))
+			return
+		}
+		c.HTML(http.StatusOK, "settings", h.settingsData(c, userID, currentUser, "", i18n.T(langOf(c), "语言偏好已保存")))
+		return
+	}
+
 	oldPassword := c.PostForm("old_password")
 	newPassword := c.PostForm("new_password")
 	confirmPassword := c.PostForm("confirm_password")
 
 	// Verify old password
 	if err := bcrypt.CompareHashAndPassword([]byte(currentUser.PasswordHash), []byte(oldPassword)); err != nil {
-		c.HTML(http.StatusBadRequest, "settings", h.settingsData(userID, currentUser, "当前密码不正确", ""))
+		c.HTML(http.StatusBadRequest, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "当前密码不正确"), ""))
 		return
 	}
 
 	if newPassword == "" {
-		c.HTML(http.StatusBadRequest, "settings", h.settingsData(userID, currentUser, "新密码不能为空", ""))
+		c.HTML(http.StatusBadRequest, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "新密码不能为空"), ""))
 		return
 	}
 
 	if newPassword != confirmPassword {
-		c.HTML(http.StatusBadRequest, "settings", h.settingsData(userID, currentUser, "两次输入的密码不一致", ""))
+		c.HTML(http.StatusBadRequest, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "两次输入的密码不一致"), ""))
 		return
 	}
 
 	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(newPassword), bcrypt.DefaultCost)
 	if err != nil {
-		c.HTML(http.StatusInternalServerError, "settings", h.settingsData(userID, currentUser, "密码加密失败", ""))
+		c.HTML(http.StatusInternalServerError, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "密码加密失败"), ""))
 		return
 	}
 
 	if err := h.stores.Users.UpdatePassword(userID, string(hashedPassword)); err != nil {
-		c.HTML(http.StatusInternalServerError, "settings", h.settingsData(userID, currentUser, "密码更新失败", ""))
+		c.HTML(http.StatusInternalServerError, "settings", h.settingsData(c, userID, currentUser, i18n.T(langOf(c), "密码更新失败"), ""))
 		return
 	}
 
-	c.HTML(http.StatusOK, "settings", h.settingsData(userID, currentUser, "", "密码修改成功"))
+	c.HTML(http.StatusOK, "settings", h.settingsData(c, userID, currentUser, "", i18n.T(langOf(c), "密码修改成功")))
 }
 
 // formatBytes converts a file size in bytes to a human-readable string.

internal/web/handlers/oauth2_state_test.go

@@ -5,6 +5,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"fmt"
 	"html/template"
 	"math"
 	"net/http"
@@ -31,7 +32,13 @@ func testTemplateFuncs() template.FuncMap {
 		"div":     func(a, b int) int { return a / b },
 		"mod":     func(a, b int) int { return a % b },
 		"ceilDiv": func(a, b int) int { return int(math.Ceil(float64(a) / float64(b))) },
-		"seq":        func(n int) []int { r := make([]int, n); for i := range r { r[i] = i + 1 }; return r },
+		"seq": func(n int) []int {
+			r := make([]int, n)
+			for i := range r {
+				r[i] = i + 1
+			}
+			return r
+		},
 		"domainName": func(domainID uint, domains []interface{}) string { return "Domain #1" },
 		"jsonify": func(v interface{}) template.JS {
 			b, _ := json.Marshal(v)
@@ -45,13 +52,16 @@ func testTemplateFuncs() template.FuncMap {
 		"mailEmail":    func(s string) string { return s },
 		"initial":      func(s string) string { return "?" },
 		"truncate":     func(s string, n int) string { return s },
-		"shortDate":    func(t time.Time) string { return t.Format("2006-01-02") },
+		"t":            func(lang, key string) string { return key },
+		"tf":           func(lang, key string, args ...interface{}) string { return fmt.Sprintf(key, args...) },
+		"htmlLang":     func(lang string) string { return "zh-CN" },
+		"shortDate":    func(lang string, t time.Time) string { return t.Format("2006-01-02") },
 		"localTime":    func(t time.Time) time.Time { return t },
-		"time12":       func(t time.Time) string { return t.Format("2006-01-02 15:04:05") },
+		"time12":       func(lang string, t time.Time) string { return t.Format("2006-01-02 15:04:05") },
-		"time12m":      func(t time.Time) string { return t.Format("2006-01-02 15:04") },
+		"time12m":      func(lang string, t time.Time) string { return t.Format("2006-01-02 15:04") },
 		"avatarStyle":  func(s string) string { return "background:#eee;color:#333" },
 		"urlPath":      func(s string) string { return url.PathEscape(s) },
-		"folderLabel":  func(s string) string { return s },
+		"folderLabel":  func(lang, s string) string { return s },
 	}
 }
 

internal/web/middleware/admin.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"mail_go/internal/db"
+	"mail_go/internal/i18n"
 
 	"github.com/gin-gonic/gin"
 )
@@ -12,16 +13,22 @@ import (
 // Must be used after AuthMiddleware so that "currentUser" is available.
 func AdminMiddleware() gin.HandlerFunc {
 	return func(c *gin.Context) {
+		lang := i18n.FromAcceptLanguage(c.GetHeader("Accept-Language"))
+		if v, ok := c.Get("lang"); ok {
+			if s, ok := v.(string); ok && i18n.Supported(s) {
+				lang = s
+			}
+		}
 		userVal, exists := c.Get("currentUser")
 		if !exists {
-			c.String(http.StatusForbidden, "禁止访问")
+			c.String(http.StatusForbidden, i18n.T(lang, "禁止访问"))
 			c.Abort()
 			return
 		}
 
 		user, ok := userVal.(*db.User)
 		if !ok || !user.IsAdmin {
-			c.String(http.StatusForbidden, "禁止访问：需要管理员权限")
+			c.String(http.StatusForbidden, i18n.T(lang, "禁止访问：需要管理员权限"))
 			c.Abort()
 			return
 		}

internal/web/middleware/auth.go

@@ -3,6 +3,7 @@ package middleware
 import (
 	"time"
 
+	"mail_go/internal/i18n"
 	"mail_go/internal/store"
 
 	"github.com/gin-contrib/sessions"
@@ -100,6 +101,10 @@ func AuthMiddleware(stores *store.Stores) gin.HandlerFunc {
 			return
 		}
 
+		// 解析界面语言：用户偏好 auto 时按浏览器 Accept-Language 选择，
+		// 最终兜底英语。模板数据与错误提示统一使用该值。
+		c.Set("lang", i18n.Resolve(user.Language, c.GetHeader("Accept-Language")))
+
 		c.Set("currentUser", user)
 		c.Set("userID", id)
 		c.Next()

internal/web/middleware/ban.go

@@ -3,6 +3,7 @@ package middleware
 import (
 	"net/http"
 
+	"mail_go/internal/i18n"
 	"mail_go/internal/store"
 
 	"github.com/gin-gonic/gin"
@@ -15,8 +16,12 @@ func BanMiddleware(stores *store.Stores) gin.HandlerFunc {
 		ip := c.ClientIP()
 		banned, entry := stores.Bans.IsBanned(ip)
 		if banned {
+			// 封禁页无登录用户，按浏览器语言渲染
+			lang := i18n.FromAcceptLanguage(c.GetHeader("Accept-Language"))
+			c.Set("lang", lang)
 			c.HTML(http.StatusForbidden, "banned", gin.H{
 				"entry": entry,
+				"Lang":  lang,
 			})
 			c.Abort()
 			return

internal/web/render_test.go

@@ -59,24 +59,24 @@ func TestRenderAllPages(t *testing.T) {
 		name string
 		data ginH
 	}{
-		{"login", ginH{"error": ""}},
+		{"login", ginH{"Lang": "zh", "error": ""}},
-		{"banned", ginH{"entry": &db.BanEntry{IPAddress: "1.2.3.4", Reason: "登录失败次数过多", FailCount: 8, ExpiresAt: now.Add(20 * time.Minute)}}},
+		{"banned", ginH{"Lang": "zh", "entry": &db.BanEntry{IPAddress: "1.2.3.4", Reason: "登录失败次数过多", FailCount: 8, ExpiresAt: now.Add(20 * time.Minute)}}},
-		{"folder", ginH{"currentUser": user, "messages": messages, "total": 5, "page": 1, "totalPages": 1, "folder": "INBOX", "activeFolder": "INBOX", "isTrash": false, "folders": folders}},
+		{"folder", ginH{"Lang": "zh", "currentUser": user, "messages": messages, "total": 5, "page": 1, "totalPages": 1, "folder": "INBOX", "activeFolder": "INBOX", "isTrash": false, "folders": folders}},
-		{"folder", ginH{"currentUser": user, "messages": messages, "total": 2, "page": 1, "totalPages": 1, "folder": "Trash", "activeFolder": "Trash", "isTrash": true, "folders": folders}},
+		{"folder", ginH{"Lang": "zh", "currentUser": user, "messages": messages, "total": 2, "page": 1, "totalPages": 1, "folder": "Trash", "activeFolder": "Trash", "isTrash": true, "folders": folders}},
-		{"view", ginH{
+		{"view", ginH{"Lang": "zh",
 			"currentUser": user, "activeFolder": "INBOX",
 			"message":     &db.Message{ID: 1, Folder: "INBOX", FromAddr: "=?UTF-8?B?5byg5LiJ?= <zhangsan@lmve.net>", ToAddr: "admin@lmve.net", Subject: "邮件系统部署完成通知", TextBody: "您好！您的 MailGo 邮件系统已成功部署。", HtmlBody: "", Date: now, IsRead: false},
 			"attachments": attachments, "inTrash": false, "folders": folders,
 		}},
-		{"compose", ginH{
+		{"compose", ginH{"Lang": "zh",
 			"currentUser": user, "activeFolder": "compose", "error": "",
 			"to": "zhangsan@lmve.net", "subject": "Re: 邮件系统部署完成通知", "bodyContent": "",
 			"usedBytes": int64(5 * 1024 * 1024), "quotaBytes": int64(5 * 1024 * 1024 * 1024),
 			"folders": folders,
 		}},
-		{"settings", ginH{"currentUser": user, "activeFolder": "settings", "error": "", "success": "", "folders": folders}},
+		{"settings", ginH{"Lang": "zh", "currentUser": user, "activeFolder": "settings", "error": "", "success": "", "folders": folders}},
-		{"admin_dashboard", ginH{"currentUser": user, "activeFolder": "admin", "domainCount": 2, "userCount": 5, "totalMails": 100, "banCount": 1, "inboxCount": 50, "sentCount": 30, "draftsCount": 10, "trashCount": 5, "inboxSize": int64(1024), "sentSize": int64(512), "totalSize": int64(2048), "todayReceived": 3, "todaySent": 2, "weekReceived": 20, "weekSent": 15}},
+		{"admin_dashboard", ginH{"Lang": "zh", "currentUser": user, "activeFolder": "admin", "domainCount": 2, "userCount": 5, "totalMails": 100, "banCount": 1, "inboxCount": 50, "sentCount": 30, "draftsCount": 10, "trashCount": 5, "inboxSize": int64(1024), "sentSize": int64(512), "totalSize": int64(2048), "todayReceived": 3, "todaySent": 2, "weekReceived": 20, "weekSent": 15}},
-		{"admin_bans", ginH{
+		{"admin_bans", ginH{"Lang": "zh",
 			"currentUser": user, "activeFolder": "bans",
 			"rows": []struct {
 				db.BanEntry
@@ -88,7 +88,7 @@ func TestRenderAllPages(t *testing.T) {
 			},
 			"total": 3, "page": 1, "pageSize": 20, "totalPages": 1,
 		}},
-		{"admin_protocol_logs", ginH{
+		{"admin_protocol_logs", ginH{"Lang": "zh",
 			"currentUser": user, "activeFolder": "protocol-logs",
 			"logs": []db.ProtocolLog{
 				{ID: 1, Protocol: db.ProtocolSMTP, Port: 25, ClientIP: "203.0.113.7", Username: "", Success: true, FailReason: "", Detail: "MAIL FROM:<spam@evil.example> RCPT×1 本地投递1", MsgCount: 1, DurationMs: 1234, CreatedAt: now},
@@ -109,7 +109,7 @@ func TestRenderAllPages(t *testing.T) {
 			},
 			"keepDays": 30,
 		}},
-		{"admin_connections", ginH{
+		{"admin_connections", ginH{"Lang": "zh",
 			"currentUser": user, "activeFolder": "connections",
 			"conns": []struct {
 				ID         uint64

internal/web/server.go

@@ -18,6 +18,7 @@ import (
 
 	"mail_go/config"
 	"mail_go/internal/connhub"
+	"mail_go/internal/i18n"
 	"mail_go/internal/imap_server"
 	"mail_go/internal/mailutil"
 	"mail_go/internal/outbound"
@@ -84,6 +85,21 @@ func templateFuncs() template.FuncMap {
 		"domainName": func(domainID uint, domains []interface{}) string {
 			return fmt.Sprintf("Domain #%d", domainID)
 		},
+		// t / tf 多语言翻译（见 internal/i18n）：t 返回译文，
+		// tf 对译文做 fmt.Sprintf（带占位符的消息）。
+		"t":  i18n.T,
+		"tf": i18n.TF,
+		// htmlLang 返回 <html lang="..."> 属性值（zh → zh-CN）。
+		"htmlLang": func(lang string) string {
+			switch i18n.Normalize(lang) {
+			case i18n.LangZh:
+				return "zh-CN"
+			case i18n.LangJa:
+				return "ja"
+			default:
+				return "en"
+			}
+		},
 		// jsonify 把任意值序列化为安全的 JS 字面量（JSON 字符串），
 		// 用于在 <script> 上下文中注入数据。encoding/json 默认转义
 		// < > &（\u003c 等），无法逃出 </script>，杜绝 script 注入。
@@ -108,12 +124,11 @@ func templateFuncs() template.FuncMap {
 		"initial": initial,
 		// truncate 折叠空白并截断到 n 个字符（用于列表摘要）。
 		"truncate": truncate,
-		// shortDate 邮件列表时间：统一 12 小时制（上午/下午）。
+		// shortDate 邮件列表时间：按界面语言输出 12 小时制。
 		// 今天显示「下午 2:35」，今年显示「08-20 下午 2:35」，
 		// 更早显示「2026-08-20 下午 2:35」。
 		"shortDate": shortDate,
-		// time12 完整时间（含秒），先转换为 Web 时区：
+		// time12 完整时间（含秒），先转换为 Web 时区。
-		// 「2026-08-20 下午 2:35:05」。
 		"time12": time12,
 		// time12m 同上但不含秒。
 		"time12m": time12m,
@@ -123,22 +138,28 @@ func templateFuncs() template.FuncMap {
 		"avatarStyle": avatarStyle,
 		// urlPath 转义文件夹名用于 URL 路径（自定义文件夹可能含中文/空格）。
 		"urlPath": url.PathEscape,
-		// folderLabel 返回文件夹的界面显示名（系统文件夹中文名，自定义原名）。
+		// folderLabel 返回文件夹的界面显示名（系统文件夹按语言翻译，自定义原名）。
-		"folderLabel": func(name string) string {
+		"folderLabel": func(lang, name string) string {
+			return folderLabel(lang, name)
+		},
+	}
+}
+
+// folderLabel 返回文件夹的界面显示名：系统文件夹按界面语言翻译，
+// 自定义文件夹原样返回。
+func folderLabel(lang, name string) string {
 	switch name {
 	case "INBOX":
-				return "收件箱"
+		return i18n.T(lang, "收件箱")
 	case "Sent":
-				return "已发送"
+		return i18n.T(lang, "已发送")
 	case "Drafts":
-				return "草稿箱"
+		return i18n.T(lang, "草稿箱")
 	case "Trash":
-				return "已删除"
+		return i18n.T(lang, "已删除")
 	default:
 		return name
 	}
-		},
-	}
 }
 
 // mailName extracts the display name from an RFC 5322 address.
@@ -186,11 +207,12 @@ func truncate(s string, n int) string {
 	return string(r[:n]) + "…"
 }
 
-// periodOf 返回 12 小时制的时间段与小时：上午/下午 + 1-12。
+// periodOf 返回 12 小时制的时间段与小时：按界面语言输出
-func periodOf(t time.Time) (string, int) {
+// 上午/下午（zh）、AM/PM（en）、午前/午後（ja），小时 1-12。
-	period := "上午"
+func periodOf(lang string, t time.Time) (string, int) {
+	period := i18n.T(lang, "上午")
 	if t.Hour() >= 12 {
-		period = "下午"
+		period = i18n.T(lang, "下午")
 	}
 	h := t.Hour() % 12
 	if h == 0 {
@@ -202,10 +224,10 @@ func periodOf(t time.Time) (string, int) {
 // shortDate 邮件列表时间（12 小时制，先按 Web 配置时区转换）：
 // 今天 → 「下午 2:35」；今年 → 「08-20 下午 2:35」；
 // 更早 → 「2026-08-20 下午 2:35」。
-func shortDate(t time.Time) string {
+func shortDate(lang string, t time.Time) string {
 	t = inWebTZ(t)
 	now := time.Now().In(t.Location())
-	period, h := periodOf(t)
+	period, h := periodOf(lang, t)
 	clock := fmt.Sprintf("%s %d:%02d", period, h, t.Minute())
 	if t.Year() == now.Year() && t.YearDay() == now.YearDay() {
 		return clock
@@ -218,16 +240,16 @@ func shortDate(t time.Time) string {
 
 // time12 完整时间（12 小时制，先按 Web 配置时区转换）：
 // 「2026-08-20 下午 2:35:05」。
-func time12(t time.Time) string {
+func time12(lang string, t time.Time) string {
 	t = inWebTZ(t)
-	period, h := periodOf(t)
+	period, h := periodOf(lang, t)
 	return fmt.Sprintf("%s %s %d:%02d:%02d", t.Format("2006-01-02"), period, h, t.Minute(), t.Second())
 }
 
 // time12m 完整时间（12 小时制，不含秒）。
-func time12m(t time.Time) string {
+func time12m(lang string, t time.Time) string {
 	t = inWebTZ(t)
-	period, h := periodOf(t)
+	period, h := periodOf(lang, t)
 	return fmt.Sprintf("%s %s %d:%02d", t.Format("2006-01-02"), period, h, t.Minute())
 }
 

internal/web/templates/admin/bans.html

@@ -1,10 +1,10 @@
 {{define "admin_bans"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>IP黑名单 - MailGo</title>
+    <title>{{t .Lang "IP黑名单"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,32 +12,32 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
                     <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;">
-                        <h2>IP 黑名单</h2>
+                        <h2>{{t .Lang "IP 黑名单"}}</h2>
-                        <span style="color:#7f8c8d;font-size:13px;">阶段性封禁：第 4 次触发起封禁，30分钟 → 3小时 → 3个月 → 半年（上限）</span>
+                        <span style="color:#7f8c8d;font-size:13px;">{{t .Lang "阶段性封禁：第 4 次触发起封禁，30分钟 → 3小时 → 3个月 → 半年（上限）"}}</span>
                     </div>
                     <table>
                         <thead>
                             <tr>
-                                <th>IP 地址</th>
+                                <th>{{t .Lang "IP 地址"}}</th>
-                                <th>状态</th>
+                                <th>{{t .Lang "状态"}}</th>
-                                <th>封禁次数</th>
+                                <th>{{t .Lang "封禁次数"}}</th>
-                                <th>失败次数</th>
+                                <th>{{t .Lang "失败次数"}}</th>
-                                <th>原因</th>
+                                <th>{{t .Lang "原因"}}</th>
-                                <th>到期时间</th>
+                                <th>{{t .Lang "到期时间"}}</th>
-                                <th>操作</th>
+                                <th>{{t .Lang "操作"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -45,21 +45,21 @@
                             <tr>
                                 <td>{{.IPAddress}}</td>
                                 <td>
-                                    {{if .Active}}<span class="badge" style="background:#e74c3c;color:#fff;">封禁中</span>
+                                    {{if .Active}}<span class="badge" style="background:#e74c3c;color:#fff;">{{t $.Lang "封禁中"}}</span>
-                                    {{else}}<span class="badge" style="background:#95a5a6;color:#fff;">已过期</span>{{end}}
+                                    {{else}}<span class="badge" style="background:#95a5a6;color:#fff;">{{t $.Lang "已过期"}}</span>{{end}}
                                 </td>
                                 <td>
                                     {{if .BanCount}}
-                                        {{if gt .BanCount 3}}第{{sub .BanCount 3}}次封禁{{else}}仅计数{{end}}
+                                        {{if gt .BanCount 3}}{{tf $.Lang "第 %d 次封禁" (sub .BanCount 3)}}{{else}}{{t $.Lang "仅计数"}}{{end}}
                                     {{else}}—{{end}}
                                 </td>
                                 <td>{{.FailCount}}</td>
-                                <td>{{if .Reason}}{{.Reason}}{{else}}—{{end}}</td>
+                                <td>{{if .Reason}}{{t $.Lang .Reason}}{{else}}—{{end}}</td>
-                                <td>{{time12 .ExpiresAt}}{{if not .Active}}（已过期）{{end}}</td>
+                                <td>{{time12 $.Lang .ExpiresAt}}{{if not .Active}}{{t $.Lang "（已过期）"}}{{end}}</td>
                                 <td>
                                     <form method="POST" action="/admin/bans/{{.ID}}/unban" style="display:inline;"
-                                          onsubmit="return confirm('确定要解封 IP {{.IPAddress}} 吗？解封后该 IP 的封禁档位将清零。');">
+                                          onsubmit="return confirm('{{tf $.Lang "确定要解封 IP %s 吗？解封后该 IP 的封禁档位将清零。" .IPAddress}}');">
-                                        <button type="submit" class="btn btn-primary btn-sm">解封</button>
+                                        <button type="submit" class="btn btn-primary btn-sm">{{t $.Lang "解封"}}</button>
                                     </form>
                                 </td>
                             </tr>
@@ -67,17 +67,17 @@
                         </tbody>
                     </table>
                     {{if not .rows}}
-                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">暂无封禁记录</p>
+                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">{{t $.Lang "暂无封禁记录"}}</p>
                     {{end}}
                 </div>
                 {{if .totalPages}}
                 <div class="pagination">
                     {{if gt .page 1}}
-                    <a href="/admin/bans?page={{sub .page 1}}">上一页</a>
+                    <a href="/admin/bans?page={{sub .page 1}}">{{t $.Lang "上一页"}}</a>
                     {{end}}
-                    <span>第 {{.page}} / {{.totalPages}} 页（共 {{.total}} 条）</span>
+                    <span>{{tf $.Lang "第 %d / %d 页（共 %d 条）" .page .totalPages .total}}</span>
                     {{if lt .page .totalPages}}
-                    <a href="/admin/bans?page={{add .page 1}}">下一页</a>
+                    <a href="/admin/bans?page={{add .page 1}}">{{t $.Lang "下一页"}}</a>
                     {{end}}
                 </div>
                 {{end}}

internal/web/templates/admin/connections.html

@@ -1,10 +1,10 @@
 {{define "admin_connections"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>当前连接 - MailGo</title>
+    <title>{{t .Lang "当前连接"}} - MailGo</title>
     <meta http-equiv="refresh" content="5">
     {{template "styles" .}}
 </head>
@@ -13,26 +13,26 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-                <a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+                <a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;">
-                    <h2>当前连接（SMTP / IMAP / POP3）</h2>
+                    <h2>{{t .Lang "当前连接（SMTP / IMAP / POP3）"}}</h2>
-                    <span style="color:#7f8c8d;font-size:13px;">每 5 秒自动刷新</span>
+                    <span style="color:#7f8c8d;font-size:13px;">{{t .Lang "每 5 秒自动刷新"}}</span>
                 </div>
 
                 <div style="margin-bottom:24px;">
                     <div class="stat-card">
                         <h3>{{.total}}</h3>
-                        <p>当前连接总数</p>
+                        <p>{{t .Lang "当前连接总数"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{.smtpCount}}</h3>
@@ -53,15 +53,15 @@
                         <thead>
                             <tr>
                                 <th>ID</th>
-                                <th>协议</th>
+                                <th>{{t .Lang "协议"}}</th>
-                                <th>来源 IP</th>
+                                <th>{{t .Lang "来源 IP"}}</th>
-                                <th>端口</th>
+                                <th>{{t .Lang "端口"}}</th>
-                                <th>用户名</th>
+                                <th>{{t .Lang "用户名"}}</th>
                                 <th>TLS</th>
-                                <th>连接时间</th>
+                                <th>{{t .Lang "连接时间"}}</th>
-                                <th>时长</th>
+                                <th>{{t .Lang "时长"}}</th>
-                                <th>最后活跃</th>
+                                <th>{{t .Lang "最后活跃"}}</th>
-                                <th>操作</th>
+                                <th>{{t .Lang "操作"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -76,19 +76,19 @@
                                 <td>{{.IP}}</td>
                                 <td>{{.Port}}</td>
                                 <td>{{if .User}}{{.User}}{{else}}—{{end}}</td>
-                                <td>{{if .TLS}}<span class="badge" style="background:#27ae60;color:#fff;">TLS</span>{{else}}<span class="badge" style="background:#95a5a6;color:#fff;">明文</span>{{end}}</td>
+                                <td>{{if .TLS}}<span class="badge" style="background:#27ae60;color:#fff;">TLS</span>{{else}}<span class="badge" style="background:#95a5a6;color:#fff;">{{t $.Lang "明文"}}</span>{{end}}</td>
-                                <td>{{time12 .Connected}}</td>
+                                <td>{{time12 $.Lang .Connected}}</td>
                                 <td>{{durationSeconds ($.now.Sub .Connected)}}s</td>
-                                <td>{{time12 .LastActive}}</td>
+                                <td>{{time12 $.Lang .LastActive}}</td>
                                 <td>
                                     <form method="POST" action="/admin/connections/{{.ID}}/disconnect" style="display:inline;"
-                                          onsubmit="return confirm('确定要断开 IP {{.IP}} 的所有连接并加入黑名单（180 天）吗？');">
+                                          onsubmit="return confirm('{{tf $.Lang "确定要断开 IP %s 的所有连接并加入黑名单（180 天）吗？" .IP}}');">
-                                        <button type="submit" class="btn btn-sm btn-danger">断开并封禁</button>
+                                        <button type="submit" class="btn btn-sm btn-danger">{{t $.Lang "断开并封禁"}}</button>
                                     </form>
                                 </td>
                             </tr>
                             {{else}}
-                            <tr><td colspan="10" style="text-align:center;color:#7f8c8d;">当前没有活动连接</td></tr>
+                            <tr><td colspan="10" style="text-align:center;color:#7f8c8d;">{{t $.Lang "当前没有活动连接"}}</td></tr>
                             {{end}}
                         </tbody>
                     </table>

internal/web/templates/admin/dashboard.html

@@ -1,10 +1,10 @@
 {{define "admin_dashboard"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>管理后台 - MailGo</title>
+    <title>{{t .Lang "管理后台"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,74 +12,74 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
-                <h2 style="margin-bottom:24px;">管理后台</h2>
+                <h2 style="margin-bottom:24px;">{{t .Lang "管理后台"}}</h2>
                 <div style="margin-bottom:24px;">
                     <div class="stat-card">
                         <h3>{{.domainCount}}</h3>
-                        <p>域名数</p>
+                        <p>{{t .Lang "域名数"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{.userCount}}</h3>
-                        <p>用户数</p>
+                        <p>{{t .Lang "用户数"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{.totalMails}}</h3>
-                        <p>邮件总数</p>
+                        <p>{{t .Lang "邮件总数"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{.banCount}}</h3>
-                        <p>被封IP</p>
+                        <p>{{t .Lang "被封IP"}}</p>
                     </div>
                 </div>
                 <div class="card">
-                    <h3>邮件分布</h3>
+                    <h3>{{t .Lang "邮件分布"}}</h3>
                     <table style="margin-top:12px;">
                         <thead>
                             <tr>
-                                <th>文件夹</th>
+                                <th>{{t .Lang "文件夹"}}</th>
-                                <th>邮件数</th>
+                                <th>{{t .Lang "邮件数"}}</th>
-                                <th>占用空间</th>
+                                <th>{{t .Lang "占用空间"}}</th>
                             </tr>
                         </thead>
                         <tbody>
-                            <tr><td>收件箱 (INBOX)</td><td>{{.inboxCount}}</td><td>{{formatBytes .inboxSize}}</td></tr>
+                            <tr><td>{{folderLabel .Lang "INBOX"}} (INBOX)</td><td>{{.inboxCount}}</td><td>{{formatBytes .inboxSize}}</td></tr>
-                            <tr><td>发件箱 (Sent)</td><td>{{.sentCount}}</td><td>{{formatBytes .sentSize}}</td></tr>
+                            <tr><td>{{folderLabel .Lang "Sent"}} (Sent)</td><td>{{.sentCount}}</td><td>{{formatBytes .sentSize}}</td></tr>
-                            <tr><td>草稿箱 (Drafts)</td><td>{{.draftsCount}}</td><td>—</td></tr>
+                            <tr><td>{{folderLabel .Lang "Drafts"}} (Drafts)</td><td>{{.draftsCount}}</td><td>—</td></tr>
-                            <tr><td>垃圾箱 (Trash)</td><td>{{.trashCount}}</td><td>—</td></tr>
+                            <tr><td>{{folderLabel .Lang "Trash"}} (Trash)</td><td>{{.trashCount}}</td><td>—</td></tr>
-                            <tr style="font-weight:bold;"><td>合计</td><td>{{.totalMails}}</td><td>{{formatBytes .totalSize}}</td></tr>
+                            <tr style="font-weight:bold;"><td>{{t .Lang "合计"}}</td><td>{{.totalMails}}</td><td>{{formatBytes .totalSize}}</td></tr>
                         </tbody>
                     </table>
                 </div>
                 <div class="card">
-                    <h3>收发统计</h3>
+                    <h3>{{t .Lang "收发统计"}}</h3>
                     <table style="margin-top:12px;">
                         <thead>
-                            <tr><th>时间段</th><th>收件</th><th>发件</th></tr>
+                            <tr><th>{{t .Lang "时间段"}}</th><th>{{t .Lang "收件"}}</th><th>{{t .Lang "发件"}}</th></tr>
                         </thead>
                         <tbody>
-                            <tr><td>今日</td><td>{{.todayReceived}}</td><td>{{.todaySent}}</td></tr>
+                            <tr><td>{{t .Lang "今日"}}</td><td>{{.todayReceived}}</td><td>{{.todaySent}}</td></tr>
-                            <tr><td>近 7 天</td><td>{{.weekReceived}}</td><td>{{.weekSent}}</td></tr>
+                            <tr><td>{{t .Lang "近 7 天"}}</td><td>{{.weekReceived}}</td><td>{{.weekSent}}</td></tr>
                         </tbody>
                     </table>
                 </div>
                 <div class="card">
-                    <h3>快捷操作</h3>
+                    <h3>{{t .Lang "快捷操作"}}</h3>
                     <p style="margin-top:12px;">
-                        <a href="/admin/domains/new" class="btn btn-primary">新增域名</a>
+                        <a href="/admin/domains/new" class="btn btn-primary">{{t .Lang "新增域名"}}</a>
-                        <a href="/admin/users/new" class="btn btn-primary" style="margin-left:8px;">新增用户</a>
+                        <a href="/admin/users/new" class="btn btn-primary" style="margin-left:8px;">{{t .Lang "新增用户"}}</a>
-                        <a href="/admin/mails" class="btn btn-primary" style="margin-left:8px;">查看所有邮件</a>
+                        <a href="/admin/mails" class="btn btn-primary" style="margin-left:8px;">{{t .Lang "查看所有邮件"}}</a>
-                        <a href="/admin/bans" class="btn btn-primary" style="margin-left:8px;">IP黑名单</a>
+                        <a href="/admin/bans" class="btn btn-primary" style="margin-left:8px;">{{t .Lang "IP黑名单"}}</a>
                     </p>
                 </div>
             </div>

internal/web/templates/admin/dns_hint.html

@@ -1,10 +1,10 @@
 {{define "admin_dns_hint"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>DNS配置 - MailGo</title>
+    <title>{{t .Lang "DNS配置"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,39 +12,39 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
-                    <h2 style="margin-bottom:16px;">DNS 配置提示 — {{.domain.Name}}</h2>
+                    <h2 style="margin-bottom:16px;">{{tf .Lang "DNS 配置提示 — %s" .domain.Name}}</h2>
-                    <p style="margin-bottom:16px;color:#7f8c8d;">请在您的 DNS 服务商处添加以下记录：</p>
+                    <p style="margin-bottom:16px;color:#7f8c8d;">{{t .Lang "请在您的 DNS 服务商处添加以下记录："}}</p>
 
-                    <h4 style="margin-bottom:8px;">MX 记录</h4>
+                    <h4 style="margin-bottom:8px;">{{t .Lang "MX 记录"}}</h4>
                     <div class="dns-record">@ IN MX 10 mail.{{.domain.Name}}.</div>
 
-                    <h4 style="margin-bottom:8px;">SPF 记录 (TXT)</h4>
+                    <h4 style="margin-bottom:8px;">{{t .Lang "SPF 记录 (TXT)"}}</h4>
                     <div class="dns-record">@ IN TXT "v=spf1 mx -all"</div>
 
-                    <h4 style="margin-bottom:8px;">DKIM 记录 (TXT)</h4>
+                    <h4 style="margin-bottom:8px;">{{t .Lang "DKIM 记录 (TXT)"}}</h4>
                     {{if .domain.DkimPublicKey}}
                     <div class="dns-record">default._domainkey.{{.domain.Name}}. IN TXT "{{.dkimRecord}}"</div>
                     {{else}}
-                    <div class="dns-record" style="color:#e67e22;">⚠️ DKIM 密钥尚未生成，请编辑域名重新生成。</div>
+                    <div class="dns-record" style="color:#e67e22;">{{t .Lang "⚠️ DKIM 密钥尚未生成，请编辑域名重新生成。"}}</div>
                     {{end}}
 
-                    <h4 style="margin-bottom:8px;">DMARC 记录</h4>
+                    <h4 style="margin-bottom:8px;">{{t .Lang "DMARC 记录"}}</h4>
                     <div class="dns-record">_dmarc.{{.domain.Name}}. IN TXT "v=DMARC1; p=none; rua=mailto:postmaster@{{.domain.Name}}"</div>
 
                     <div style="margin-top:24px;">
-                        <a href="/admin/domains" class="btn" style="background:#bdc3c7;color:#fff;">返回域名列表</a>
+                        <a href="/admin/domains" class="btn" style="background:#bdc3c7;color:#fff;">{{t .Lang "返回域名列表"}}</a>
                     </div>
                 </div>
             </div>

internal/web/templates/admin/domain_form.html

@@ -1,10 +1,10 @@
 {{define "admin_domain_form"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>{{if .isEdit}}编辑域名{{else}}新增域名{{end}} - MailGo</title>
+    <title>{{if .isEdit}}{{t .Lang "编辑域名"}}{{else}}{{t .Lang "新增域名"}}{{end}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,24 +12,24 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
-                    <h2 style="margin-bottom:16px;">{{if .isEdit}}编辑域名{{else}}新增域名{{end}}</h2>
+                    <h2 style="margin-bottom:16px;">{{if .isEdit}}{{t .Lang "编辑域名"}}{{else}}{{t .Lang "新增域名"}}{{end}}</h2>
                     {{if .error}}<div class="alert alert-error">{{.error}}</div>{{end}}
                     {{if .caddyMsg}}<div class="alert {{if eq .caddyMsgType "success"}}alert-success{{else}}alert-error{{end}}">{{.caddyMsg}}</div>{{end}}
                     <form method="POST" action="{{if .isEdit}}/admin/domains/{{.domain.ID}}{{else}}/admin/domains{{end}}">
                         <div class="form-group">
-                            <label>域名</label>
+                            <label>{{t .Lang "域名"}}</label>
                             {{if .isEdit}}
                             <input type="text" name="name" value="{{.domain.Name}}" disabled style="background:#f5f5f5;">
                             {{else}}
@@ -37,45 +37,45 @@
                             {{end}}
                         </div>
                         <div class="form-group">
-                            <label>SMTP 端口</label>
+                            <label>{{t .Lang "SMTP 端口"}}</label>
                             <input type="number" name="smtp_port" value="{{.domain.SmtpPort}}" placeholder="25">
                         </div>
                         <div class="form-group">
-                            <label>IMAP 端口</label>
+                            <label>{{t .Lang "IMAP 端口"}}</label>
                             <input type="number" name="imap_port" value="{{.domain.ImapPort}}" placeholder="143">
                         </div>
                         <div class="form-group">
-                            <label>POP3 端口</label>
+                            <label>{{t .Lang "POP3 端口"}}</label>
                             <input type="number" name="pop3_port" value="{{.domain.Pop3Port}}" placeholder="110">
                         </div>
                         <div class="form-group">
                             <label>
                                 <input type="checkbox" name="tls_enabled" id="tls_enabled" {{if .domain.TlsEnabled}}checked{{end}} onchange="togglePorts()">
-                                启用 TLS
+                                {{t .Lang "启用 TLS"}}
                             </label>
-                            <p style="color:#7f8c8d;font-size:12px;margin-top:4px;">勾选后端口将自动切换为 SSL/TLS 标准端口</p>
+                            <p style="color:#7f8c8d;font-size:12px;margin-top:4px;">{{t .Lang "勾选后端口将自动切换为 SSL/TLS 标准端口"}}</p>
                         </div>
                         {{if .isEdit}}
                         <div id="tls_cert_fields" style="display:none;">
                             <div class="form-group">
-                                <label>TLS 私钥 PEM</label>
+                                <label>{{t .Lang "TLS 私钥 PEM"}}</label>
                                 <textarea name="tls_private_key" rows="8" placeholder="-----BEGIN PRIVATE KEY-----&#10;...&#10;-----END PRIVATE KEY-----" style="font-family:monospace;"></textarea>
-                                <p style="color:#7f8c8d;font-size:12px;margin-top:4px;">私钥不会回显；留空则保留现有私钥。</p>
+                                <p style="color:#7f8c8d;font-size:12px;margin-top:4px;">{{t .Lang "私钥不会回显；留空则保留现有私钥。"}}</p>
                             </div>
                             <div class="form-group">
-                                <label>TLS 公钥证书 PEM</label>
+                                <label>{{t .Lang "TLS 公钥证书 PEM"}}</label>
                                 <textarea name="tls_public_cert" rows="8" placeholder="-----BEGIN CERTIFICATE-----&#10;...&#10;-----END CERTIFICATE-----" style="font-family:monospace;">{{.tlsPublicCert}}</textarea>
                                 {{if .tlsCertConfigured}}
-                                <p style="color:#27ae60;font-size:12px;margin-top:4px;">✅ TLS 证书已配置；上传新证书后自动热加载生效。</p>
+                                <p style="color:#27ae60;font-size:12px;margin-top:4px;">{{t .Lang "✅ TLS 证书已配置；上传新证书后自动热加载生效。"}}</p>
                                 {{else}}
-                                <p style="color:#e67e22;font-size:12px;margin-top:4px;">⚠️ TLS 证书未配置，启用 TLS 时必须同时填写私钥和证书。</p>
+                                <p style="color:#e67e22;font-size:12px;margin-top:4px;">{{t .Lang "⚠️ TLS 证书未配置，启用 TLS 时必须同时填写私钥和证书。"}}</p>
                                 {{end}}
                             </div>
                         </div>
                         <div class="form-group" style="margin-top:4px;">
-                            <label>从 Caddy 获取证书</label>
+                            <label>{{t .Lang "从 Caddy 获取证书"}}</label>
-                            <p style="color:#7f8c8d;font-size:12px;margin-top:2px;margin-bottom:8px;">若该域名已由本机 Caddy 托管 HTTPS（自动签发证书），可一键导入其证书与私钥，并自动启用 TLS；证书热加载，无需重启服务。</p>
+                            <p style="color:#7f8c8d;font-size:12px;margin-top:2px;margin-bottom:8px;">{{t .Lang "若该域名已由本机 Caddy 托管 HTTPS（自动签发证书），可一键导入其证书与私钥，并自动启用 TLS；证书热加载，无需重启服务。"}}</p>
-                            <button type="button" class="btn" id="btn_fetch_caddy" onclick="fetchCaddyCert()" style="background:#2e86de;color:#fff;">🔒 从 Caddy 获取证书</button>
+                            <button type="button" class="btn" id="btn_fetch_caddy" onclick="fetchCaddyCert()" style="background:#2e86de;color:#fff;">{{t .Lang "🔒 从 Caddy 获取证书"}}</button>
                             <span id="caddy_fetch_msg" style="margin-left:10px;font-size:12px;color:#7f8c8d;"></span>
                             <script>
                             async function fetchCaddyCert() {
@@ -83,7 +83,7 @@
                                 var msg = document.getElementById('caddy_fetch_msg');
                                 btn.disabled = true;
                                 var oldText = btn.textContent;
-                                btn.textContent = '获取中…';
+                                btn.textContent = '{{t .Lang "获取中…"}}';
                                 msg.textContent = '';
                                 try {
                                     var resp = await fetch('/admin/domains/{{.domain.ID}}/fetch-caddy-cert', { method: 'POST' });
@@ -91,9 +91,9 @@
                                         window.location.href = resp.url;
                                         return;
                                     }
-                                    msg.textContent = '获取失败: ' + await resp.text();
+                                    msg.textContent = '{{t .Lang "获取失败"}}: ' + await resp.text();
                                 } catch (e) {
-                                    msg.textContent = '请求失败: ' + e;
+                                    msg.textContent = '{{t .Lang "请求失败"}}: ' + e;
                                 }
                                 btn.disabled = false;
                                 btn.textContent = oldText;
@@ -118,17 +118,17 @@
                         <div class="form-group">
                             <label>
                                 <input type="checkbox" name="regenerate_dkim">
-                                重新生成 DKIM 密钥
+                                {{t .Lang "重新生成 DKIM 密钥"}}
                             </label>
                             {{if .domain.DkimPublicKey}}
-                            <p style="color:#27ae60;font-size:12px;margin-top:4px;">✅ DKIM 密钥已配置</p>
+                            <p style="color:#27ae60;font-size:12px;margin-top:4px;">{{t .Lang "✅ DKIM 密钥已配置"}}</p>
                             {{else}}
-                            <p style="color:#e67e22;font-size:12px;margin-top:4px;">⚠️ DKIM 密钥未配置</p>
+                            <p style="color:#e67e22;font-size:12px;margin-top:4px;">{{t .Lang "⚠️ DKIM 密钥未配置"}}</p>
                             {{end}}
                         </div>
                         {{end}}
-                        <button type="submit" class="btn btn-primary">{{if .isEdit}}保存更改{{else}}创建域名{{end}}</button>
+                        <button type="submit" class="btn btn-primary">{{if .isEdit}}{{t .Lang "保存更改"}}{{else}}{{t .Lang "创建域名"}}{{end}}</button>
-                        <a href="/admin/domains" class="btn" style="margin-left:8px;background:#bdc3c7;color:#fff;">取消</a>
+                        <a href="/admin/domains" class="btn" style="margin-left:8px;background:#bdc3c7;color:#fff;">{{t .Lang "取消"}}</a>
                     </form>
                 </div>
             </div>

internal/web/templates/admin/domains.html

@@ -1,10 +1,10 @@
 {{define "admin_domains"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>域名管理 - MailGo</title>
+    <title>{{t .Lang "域名管理"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,35 +12,35 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
                     <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;">
-                        <h2>域名列表</h2>
+                        <h2>{{t .Lang "域名列表"}}</h2>
-                        <a href="/admin/domains/new" class="btn btn-primary">新增域名</a>
+                        <a href="/admin/domains/new" class="btn btn-primary">{{t .Lang "新增域名"}}</a>
                     </div>
                     {{if not .domains}}
-                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">暂无域名</p>
+                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">{{t $.Lang "暂无域名"}}</p>
                     {{else}}
                     <table>
                         <thead>
                             <tr>
                                 <th>ID</th>
-                                <th>域名</th>
+                                <th>{{t $.Lang "域名"}}</th>
                                 <th>SMTP</th>
                                 <th>IMAP</th>
                                 <th>POP3</th>
                                 <th>TLS</th>
-                                <th>操作</th>
+                                <th>{{t $.Lang "操作"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -53,11 +53,11 @@
                                 <td>{{.Pop3Port}}</td>
                                 <td>{{if .TlsEnabled}}✅{{else}}❌{{end}}</td>
                                 <td>
-                                    <a href="/admin/domains/{{.ID}}/edit" class="btn btn-primary btn-sm">编辑</a>
+                                    <a href="/admin/domains/{{.ID}}/edit" class="btn btn-primary btn-sm">{{t $.Lang "编辑"}}</a>
                                     <a href="/admin/domains/{{.ID}}/dns" class="btn btn-primary btn-sm">DNS</a>
                                     <form method="POST" action="/admin/domains/{{.ID}}/delete" style="display:inline;"
-                                          onsubmit="return confirm('确定要删除域名 {{.Name}} 吗？删除域名将导致关联用户无法收发邮件！');">
+                                          onsubmit="return confirm('{{tf $.Lang "确定要删除域名 %s 吗？删除域名将导致关联用户无法收发邮件！" .Name}}');">
-                                        <button type="submit" class="btn btn-danger btn-sm">删除</button>
+                                        <button type="submit" class="btn btn-danger btn-sm">{{t $.Lang "删除"}}</button>
                                     </form>
                                 </td>
                             </tr>
@@ -69,11 +69,11 @@
                 {{if .totalPages}}
                 <div class="pagination">
                     {{if gt .page 1}}
-                    <a href="/admin/domains?page={{sub .page 1}}">上一页</a>
+                    <a href="/admin/domains?page={{sub .page 1}}">{{t $.Lang "上一页"}}</a>
                     {{end}}
-                    <span>第 {{.page}} / {{.totalPages}} 页</span>
+                    <span>{{tf $.Lang "第 %d / %d 页" .page .totalPages}}</span>
                     {{if lt .page .totalPages}}
-                    <a href="/admin/domains?page={{add .page 1}}">下一页</a>
+                    <a href="/admin/domains?page={{add .page 1}}">{{t $.Lang "下一页"}}</a>
                     {{end}}
                 </div>
                 {{end}}

internal/web/templates/admin/mail_view.html

@@ -1,10 +1,10 @@
 {{define "admin_mail_view"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>查看邮件 - MailGo 管理后台</title>
+    <title>{{t .Lang "查看邮件"}} - MailGo {{t .Lang "管理后台"}}</title>
     {{template "styles" .}}
     <style>
         .mail-body-iframe {
@@ -21,29 +21,29 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" class="active">所有邮件</a>
+                <a href="/admin/mails" class="active">{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
                     <div style="margin-bottom:16px;">
-                        <a href="/admin/mails" class="btn" style="background:#bdc3c7;color:#fff;">返回邮件列表</a>
+                        <a href="/admin/mails" class="btn" style="background:#bdc3c7;color:#fff;">{{t .Lang "返回邮件列表"}}</a>
                     </div>
-                    <h2>{{if .message.Subject}}{{.message.Subject}}{{else}}(无主题){{end}}</h2>
+                    <h2>{{if .message.Subject}}{{.message.Subject}}{{else}}{{t .Lang "(无主题)"}}{{end}}</h2>
                     <div class="mail-meta" style="margin-top:12px;">
-                        <p><strong>发件人:</strong> {{decodeHeader .message.FromAddr}}</p>
+                        <p><strong>{{t .Lang "发件人:"}}</strong> {{decodeHeader .message.FromAddr}}</p>
-                        <p><strong>收件人:</strong> {{.message.ToAddr}}</p>
+                        <p><strong>{{t .Lang "收件人:"}}</strong> {{.message.ToAddr}}</p>
-                        {{if .message.CcAddr}}<p><strong>抄送:</strong> {{.message.CcAddr}}</p>{{end}}
+                        {{if .message.CcAddr}}<p><strong>{{t .Lang "抄送:"}}</strong> {{.message.CcAddr}}</p>{{end}}
-                        <p><strong>所属用户:</strong> {{if .message.User.ID}}{{.message.User.Username}}{{else}}—{{end}}</p>
+                        <p><strong>{{t .Lang "所属用户:"}}</strong> {{if .message.User.ID}}{{.message.User.Username}}{{else}}—{{end}}</p>
-                        <p><strong>文件夹:</strong> {{.message.Folder}}</p>
+                        <p><strong>{{t .Lang "文件夹:"}}</strong> {{.message.Folder}}</p>
-                        <p><strong>时间:</strong> {{time12 .message.Date}}</p>
+                        <p><strong>{{t .Lang "时间:"}}</strong> {{time12 .Lang .message.Date}}</p>
                     </div>
                     <div class="mail-body">
                         {{if .message.HtmlBody}}
@@ -54,7 +54,7 @@
                     </div>
                     {{if .attachments}}
                     <div class="attachment-list">
-                        <h4 style="margin-bottom:8px;">附件</h4>
+                        <h4 style="margin-bottom:8px;">{{t .Lang "附件列表"}}</h4>
                         {{range .attachments}}
                         <div class="attachment-item">
                             📎 <a href="/admin/attachment/{{.ID}}">{{.FileName}}</a>

internal/web/templates/admin/mails.html

@@ -1,10 +1,10 @@
 {{define "admin_mails"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>所有邮件 - MailGo</title>
+    <title>{{t .Lang "所有邮件"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,38 +12,38 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
-                    <h2 style="margin-bottom:16px;">所有邮件</h2>
+                    <h2 style="margin-bottom:16px;">{{t .Lang "所有邮件"}}</h2>
                     <div style="margin-bottom:16px;">
-                        <a href="/admin/mails" {{if eq .folder ""}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>全部</a>
+                        <a href="/admin/mails" {{if eq .folder ""}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>{{t .Lang "全部"}}</a>
                         <a href="/admin/mails?folder=INBOX" {{if eq .folder "INBOX"}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>INBOX</a>
                         <a href="/admin/mails?folder=Sent" {{if eq .folder "Sent"}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>Sent</a>
                         <a href="/admin/mails?folder=Drafts" {{if eq .folder "Drafts"}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>Drafts</a>
                         <a href="/admin/mails?folder=Trash" {{if eq .folder "Trash"}}class="btn btn-primary"{{else}}class="btn" style="background:#ecf0f1;color:#333;"{{end}}>Trash</a>
                     </div>
                     {{if not .messages}}
-                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">暂无邮件</p>
+                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">{{t $.Lang "暂无邮件"}}</p>
                     {{else}}
                     <table>
                         <thead>
                             <tr>
-                                <th>发件人</th>
+                                <th>{{t $.Lang "发件人"}}</th>
-                                <th>收件人</th>
+                                <th>{{t $.Lang "收件人"}}</th>
-                                <th>主题</th>
+                                <th>{{t $.Lang "主题"}}</th>
-                                <th>所属用户</th>
+                                <th>{{t $.Lang "所属用户"}}</th>
-                                <th>文件夹</th>
+                                <th>{{t $.Lang "文件夹"}}</th>
-                                <th>日期</th>
+                                <th>{{t $.Lang "日期"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -54,7 +54,7 @@
                                 <td>{{.Subject}}</td>
                                 <td>{{if .User.ID}}{{.User.Username}}{{else}}—{{end}}</td>
                                 <td>{{.Folder}}</td>
-                                <td>{{time12m .Date}}</td>
+                                <td>{{time12m $.Lang .Date}}</td>
                             </tr>
                         {{end}}
                         </tbody>
@@ -64,11 +64,11 @@
                 {{if .totalPages}}
                 <div class="pagination">
                     {{if gt .page 1}}
-                    <a href="/admin/mails?page={{sub .page 1}}{{if .folder}}&folder={{.folder}}{{end}}">上一页</a>
+                    <a href="/admin/mails?page={{sub .page 1}}{{if .folder}}&folder={{.folder}}{{end}}">{{t $.Lang "上一页"}}</a>
                     {{end}}
-                    <span>第 {{.page}} / {{.totalPages}} 页</span>
+                    <span>{{tf $.Lang "第 %d / %d 页" .page .totalPages}}</span>
                     {{if lt .page .totalPages}}
-                    <a href="/admin/mails?page={{add .page 1}}{{if .folder}}&folder={{.folder}}{{end}}">下一页</a>
+                    <a href="/admin/mails?page={{add .page 1}}{{if .folder}}&folder={{.folder}}{{end}}">{{t $.Lang "下一页"}}</a>
                     {{end}}
                 </div>
                 {{end}}

internal/web/templates/admin/outbound.html

@@ -1,10 +1,10 @@
 {{define "admin_outbound"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>外发队列 - MailGo</title>
+    <title>{{t .Lang "外发队列"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,60 +12,60 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
-                <h2 style="margin-bottom:24px;">外发队列</h2>
+                <h2 style="margin-bottom:24px;">{{t .Lang "外发队列"}}</h2>
 
                 <div style="margin-bottom:24px;">
                     <div class="stat-card">
                         <h3>{{index .statCounts "pending"}}</h3>
-                        <p>待发送</p>
+                        <p>{{t .Lang "待发送"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{index .statCounts "deferred"}}</h3>
-                        <p>等待重试</p>
+                        <p>{{t .Lang "等待重试"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{index .statCounts "sent"}}</h3>
-                        <p>已送达</p>
+                        <p>{{t .Lang "已送达"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{index .statCounts "failed"}}</h3>
-                        <p>失败</p>
+                        <p>{{t .Lang "失败"}}</p>
                     </div>
                 </div>
 
                 <div class="card">
                     <div style="margin-bottom:12px;">
-                        <a href="/admin/outbound" class="btn btn-sm {{if eq .status ""}}btn-primary{{end}}" style="background:{{if eq .status ""}}#3498db{{else}}#ecf0f1{{end}};color:{{if eq .status ""}}#fff{{else}}#333{{end}};">全部</a>
+                        <a href="/admin/outbound" class="btn btn-sm {{if eq .status ""}}btn-primary{{end}}" style="background:{{if eq .status ""}}#3498db{{else}}#ecf0f1{{end}};color:{{if eq .status ""}}#fff{{else}}#333{{end}};">{{t .Lang "全部"}}</a>
-                        <a href="/admin/outbound?status=pending" class="btn btn-sm">待发送</a>
+                        <a href="/admin/outbound?status=pending" class="btn btn-sm">{{t .Lang "待发送"}}</a>
-                        <a href="/admin/outbound?status=deferred" class="btn btn-sm">等待重试</a>
+                        <a href="/admin/outbound?status=deferred" class="btn btn-sm">{{t .Lang "等待重试"}}</a>
-                        <a href="/admin/outbound?status=sent" class="btn btn-sm">已送达</a>
+                        <a href="/admin/outbound?status=sent" class="btn btn-sm">{{t .Lang "已送达"}}</a>
-                        <a href="/admin/outbound?status=failed" class="btn btn-sm">失败</a>
+                        <a href="/admin/outbound?status=failed" class="btn btn-sm">{{t .Lang "失败"}}</a>
-                        <a href="/admin/outbound?status=canceled" class="btn btn-sm">已取消</a>
+                        <a href="/admin/outbound?status=canceled" class="btn btn-sm">{{t .Lang "已取消"}}</a>
                     </div>
 
                     <table>
                         <thead>
                             <tr>
                                 <th>ID</th>
-                                <th>发件人</th>
+                                <th>{{t .Lang "发件人"}}</th>
-                                <th>收件人</th>
+                                <th>{{t .Lang "收件人"}}</th>
-                                <th>状态</th>
+                                <th>{{t .Lang "状态"}}</th>
-                                <th>尝试次数</th>
+                                <th>{{t .Lang "尝试次数"}}</th>
-                                <th>下次重试</th>
+                                <th>{{t .Lang "下次重试"}}</th>
-                                <th>最后响应 / 错误</th>
+                                <th>{{t .Lang "最后响应 / 错误"}}</th>
-                                <th>创建时间</th>
+                                <th>{{t .Lang "创建时间"}}</th>
-                                <th>操作</th>
+                                <th>{{t .Lang "操作"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -75,40 +75,40 @@
                                 <td>{{.FromAddr}}</td>
                                 <td>{{.ToAddr}}</td>
                                 <td>
-                                    {{if eq .Status "pending"}}<span class="badge" style="background:#f39c12;color:#fff;">{{call $.statusText .Status}}</span>
+                                    {{if eq .Status "pending"}}<span class="badge" style="background:#f39c12;color:#fff;">{{t $.Lang (call $.statusText .Status)}}</span>
-                                    {{else if eq .Status "deferred"}}<span class="badge" style="background:#e67e22;color:#fff;">{{call $.statusText .Status}}</span>
+                                    {{else if eq .Status "deferred"}}<span class="badge" style="background:#e67e22;color:#fff;">{{t $.Lang (call $.statusText .Status)}}</span>
-                                    {{else if eq .Status "sent"}}<span class="badge" style="background:#27ae60;color:#fff;">{{call $.statusText .Status}}</span>
+                                    {{else if eq .Status "sent"}}<span class="badge" style="background:#27ae60;color:#fff;">{{t $.Lang (call $.statusText .Status)}}</span>
-                                    {{else if eq .Status "failed"}}<span class="badge badge-unread">{{call $.statusText .Status}}</span>
+                                    {{else if eq .Status "failed"}}<span class="badge badge-unread">{{t $.Lang (call $.statusText .Status)}}</span>
-                                    {{else}}<span class="badge" style="background:#95a5a6;color:#fff;">{{call $.statusText .Status}}</span>{{end}}
+                                    {{else}}<span class="badge" style="background:#95a5a6;color:#fff;">{{t $.Lang (call $.statusText .Status)}}</span>{{end}}
                                 </td>
                                 <td>{{.Attempts}}</td>
-                                <td>{{if or (eq .Status "pending") (eq .Status "deferred")}}{{time12m .NextAttemptAt}}{{else}}—{{end}}</td>
+                                <td>{{if or (eq .Status "pending") (eq .Status "deferred")}}{{time12m $.Lang .NextAttemptAt}}{{else}}—{{end}}</td>
                                 <td style="max-width:280px;word-break:break-all;">{{if .LastResponse}}{{.LastResponse}}{{else}}{{.LastError}}{{end}}</td>
-                                <td>{{time12m .CreatedAt}}</td>
+                                <td>{{time12m $.Lang .CreatedAt}}</td>
                                 <td>
                                     {{if or (eq .Status "failed") (eq .Status "deferred") (eq .Status "canceled") (eq .Status "pending")}}
                                     <form method="POST" action="/admin/outbound/{{.ID}}/retry" style="display:inline;">
-                                        <button type="submit" class="btn btn-sm btn-primary">重试</button>
+                                        <button type="submit" class="btn btn-sm btn-primary">{{t $.Lang "重试"}}</button>
                                     </form>
                                     {{end}}
                                     {{if or (eq .Status "pending") (eq .Status "deferred")}}
-                                    <form method="POST" action="/admin/outbound/{{.ID}}/cancel" style="display:inline;" onsubmit="return confirm('确认取消该投递任务？');">
+                                    <form method="POST" action="/admin/outbound/{{.ID}}/cancel" style="display:inline;" onsubmit="return confirm('{{t $.Lang "确认取消该投递任务？"}}');">
-                                        <button type="submit" class="btn btn-sm btn-danger">取消</button>
+                                        <button type="submit" class="btn btn-sm btn-danger">{{t $.Lang "取消"}}</button>
                                     </form>
                                     {{end}}
                                 </td>
                             </tr>
                             {{else}}
-                            <tr><td colspan="9" style="text-align:center;color:#7f8c8d;">队列为空</td></tr>
+                            <tr><td colspan="9" style="text-align:center;color:#7f8c8d;">{{t $.Lang "队列为空"}}</td></tr>
                             {{end}}
                         </tbody>
                     </table>
 
                     {{if gt .totalPages 1}}
                     <div class="pagination">
-                        {{if gt .page 1}}<a href="/admin/outbound?page={{sub .page 1}}&status={{.status}}">上一页</a>{{end}}
+                        {{if gt .page 1}}<a href="/admin/outbound?page={{sub .page 1}}&status={{.status}}">{{t $.Lang "上一页"}}</a>{{end}}
-                        <span class="current">第 {{.page}} / {{.totalPages}} 页</span>
+                        <span class="current">{{tf $.Lang "第 %d / %d 页" .page .totalPages}}</span>
-                        {{if lt .page .totalPages}}<a href="/admin/outbound?page={{add .page 1}}&status={{.status}}">下一页</a>{{end}}
+                        {{if lt .page .totalPages}}<a href="/admin/outbound?page={{add .page 1}}&status={{.status}}">{{t $.Lang "下一页"}}</a>{{end}}
                     </div>
                     {{end}}
                 </div>

internal/web/templates/admin/protocol_logs.html

@@ -1,10 +1,10 @@
 {{define "admin_protocol_logs"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>协议日志 - MailGo</title>
+    <title>{{t .Lang "协议日志"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,41 +12,41 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;">
-                    <h2>协议日志（SMTP / IMAP / POP3）</h2>
+                    <h2>{{t .Lang "协议日志（SMTP / IMAP / POP3）"}}</h2>
                     <form method="POST" action="/admin/protocol-logs/cleanup" style="display:inline;"
-                          onsubmit="return confirm('确认清理 {{.keepDays}} 天前的协议日志？');">
+                          onsubmit="return confirm('{{tf .Lang "确认清理 %d 天前的协议日志？" .keepDays}}');">
-                        <button type="submit" class="btn btn-primary">清理旧日志</button>
+                        <button type="submit" class="btn btn-primary">{{t .Lang "清理旧日志"}}</button>
                     </form>
                 </div>
 
                 <div style="margin-bottom:24px;">
                     <div class="stat-card">
                         <h3>{{index .todayStats "smtp" "fail"}}</h3>
-                        <p>今日 SMTP 失败</p>
+                        <p>{{t .Lang "今日 SMTP 失败"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{index .todayStats "imap" "fail"}}</h3>
-                        <p>今日 IMAP 失败</p>
+                        <p>{{t .Lang "今日 IMAP 失败"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{index .todayStats "pop3" "fail"}}</h3>
-                        <p>今日 POP3 失败</p>
+                        <p>{{t .Lang "今日 POP3 失败"}}</p>
                     </div>
                     <div class="stat-card">
                         <h3>{{add (add (index .allStats "smtp" "fail") (index .allStats "imap" "fail")) (index .allStats "pop3" "fail")}}</h3>
-                        <p>历史失败（全部）</p>
+                        <p>{{t .Lang "历史失败（全部）"}}</p>
                     </div>
                 </div>
 
@@ -54,45 +54,45 @@
                     <form method="GET" action="/admin/protocol-logs" style="margin-bottom:16px;">
                         <div style="display:flex;flex-wrap:wrap;gap:12px;align-items:center;">
                             <select name="protocol" style="padding:6px 10px;">
-                                <option value="">全部协议</option>
+                                <option value="">{{t .Lang "全部协议"}}</option>
                                 <option value="smtp" {{if eq .filter.protocol "smtp"}}selected{{end}}>SMTP</option>
                                 <option value="imap" {{if eq .filter.protocol "imap"}}selected{{end}}>IMAP</option>
                                 <option value="pop3" {{if eq .filter.protocol "pop3"}}selected{{end}}>POP3</option>
                             </select>
                             <select name="success" style="padding:6px 10px;">
-                                <option value="">全部状态</option>
+                                <option value="">{{t .Lang "全部状态"}}</option>
-                                <option value="success" {{if eq .filter.success "success"}}selected{{end}}>成功</option>
+                                <option value="success" {{if eq .filter.success "success"}}selected{{end}}>{{t .Lang "成功"}}</option>
-                                <option value="fail" {{if eq .filter.success "fail"}}selected{{end}}>失败</option>
+                                <option value="fail" {{if eq .filter.success "fail"}}selected{{end}}>{{t .Lang "失败"}}</option>
                             </select>
-                            <input type="text" name="ip" placeholder="来源 IP（模糊）" value="{{.filter.ip}}" style="padding:6px 10px;width:160px;">
+                            <input type="text" name="ip" placeholder="{{t .Lang "来源 IP（模糊）"}}" value="{{.filter.ip}}" style="padding:6px 10px;width:160px;">
-                            <input type="text" name="username" placeholder="用户名（模糊）" value="{{.filter.username}}" style="padding:6px 10px;width:160px;">
+                            <input type="text" name="username" placeholder="{{t .Lang "用户名（模糊）"}}" value="{{.filter.username}}" style="padding:6px 10px;width:160px;">
                             <input type="date" name="from" value="{{.filter.from}}" style="padding:6px 10px;">
-                            <span>至</span>
+                            <span>{{t .Lang "至"}}</span>
                             <input type="date" name="to" value="{{.filter.to}}" style="padding:6px 10px;">
-                            <button type="submit" class="btn btn-sm btn-primary">筛选</button>
+                            <button type="submit" class="btn btn-sm btn-primary">{{t .Lang "筛选"}}</button>
-                            <a href="/admin/protocol-logs" class="btn btn-sm">重置</a>
+                            <a href="/admin/protocol-logs" class="btn btn-sm">{{t .Lang "重置"}}</a>
                         </div>
                     </form>
 
                     <table>
                         <thead>
                             <tr>
-                                <th>时间</th>
+                                <th>{{t .Lang "时间"}}</th>
-                                <th>协议</th>
+                                <th>{{t .Lang "协议"}}</th>
-                                <th>端口</th>
+                                <th>{{t .Lang "端口"}}</th>
-                                <th>来源 IP</th>
+                                <th>{{t .Lang "来源 IP"}}</th>
-                                <th>用户名</th>
+                                <th>{{t .Lang "用户名"}}</th>
-                                <th>状态</th>
+                                <th>{{t .Lang "状态"}}</th>
-                                <th>失败原因</th>
+                                <th>{{t .Lang "失败原因"}}</th>
-                                <th>操作摘要</th>
+                                <th>{{t .Lang "操作摘要"}}</th>
-                                <th>消息数</th>
+                                <th>{{t .Lang "消息数"}}</th>
-                                <th>时长</th>
+                                <th>{{t .Lang "时长"}}</th>
                             </tr>
                         </thead>
                         <tbody>
                             {{range .logs}}
                             <tr>
-                                <td style="white-space:nowrap;">{{time12 .CreatedAt}}</td>
+                                <td style="white-space:nowrap;">{{time12 $.Lang .CreatedAt}}</td>
                                 <td>
                                     {{if eq .Protocol "smtp"}}<span class="badge" style="background:#3498db;color:#fff;">SMTP</span>
                                     {{else if eq .Protocol "imap"}}<span class="badge" style="background:#9b59b6;color:#fff;">IMAP</span>
@@ -102,8 +102,8 @@
                                 <td>{{.ClientIP}}</td>
                                 <td>{{if .Username}}{{.Username}}{{else}}—{{end}}</td>
                                 <td>
-                                    {{if .Success}}<span class="badge" style="background:#27ae60;color:#fff;">成功</span>
+                                    {{if .Success}}<span class="badge" style="background:#27ae60;color:#fff;">{{t $.Lang "成功"}}</span>
-                                    {{else}}<span class="badge badge-unread">失败</span>{{end}}
+                                    {{else}}<span class="badge badge-unread">{{t $.Lang "失败"}}</span>{{end}}
                                 </td>
                                 <td style="max-width:200px;">{{if .FailReason}}{{.FailReason}}{{else}}—{{end}}</td>
                                 <td style="max-width:320px;word-break:break-all;font-size:13px;color:#555;">{{.Detail}}</td>
@@ -111,16 +111,16 @@
                                 <td>{{if .DurationMs}}{{div .DurationMs 1000}}s{{else}}—{{end}}</td>
                             </tr>
                             {{else}}
-                            <tr><td colspan="10" style="text-align:center;color:#7f8c8d;">暂无记录</td></tr>
+                            <tr><td colspan="10" style="text-align:center;color:#7f8c8d;">{{t $.Lang "暂无记录"}}</td></tr>
                             {{end}}
                         </tbody>
                     </table>
 
                     {{if gt .totalPages 1}}
                     <div class="pagination">
-                        {{if gt .page 1}}<a href="/admin/protocol-logs?page={{sub .page 1}}&protocol={{.filter.protocol}}&success={{.filter.success}}&ip={{.filter.ip}}&username={{.filter.username}}&from={{.filter.from}}&to={{.filter.to}}">上一页</a>{{end}}
+                        {{if gt .page 1}}<a href="/admin/protocol-logs?page={{sub .page 1}}&protocol={{.filter.protocol}}&success={{.filter.success}}&ip={{.filter.ip}}&username={{.filter.username}}&from={{.filter.from}}&to={{.filter.to}}">{{t $.Lang "上一页"}}</a>{{end}}
-                        <span class="current">第 {{.page}} / {{.totalPages}} 页（共 {{.total}} 条）</span>
+                        <span class="current">{{tf $.Lang "第 %d / %d 页（共 %d 条）" .page .totalPages .total}}</span>
-                        {{if lt .page .totalPages}}<a href="/admin/protocol-logs?page={{add .page 1}}&protocol={{.filter.protocol}}&success={{.filter.success}}&ip={{.filter.ip}}&username={{.filter.username}}&from={{.filter.from}}&to={{.filter.to}}">下一页</a>{{end}}
+                        {{if lt .page .totalPages}}<a href="/admin/protocol-logs?page={{add .page 1}}&protocol={{.filter.protocol}}&success={{.filter.success}}&ip={{.filter.ip}}&username={{.filter.username}}&from={{.filter.from}}&to={{.filter.to}}">{{t $.Lang "下一页"}}</a>{{end}}
                     </div>
                     {{end}}
                 </div>

internal/web/templates/admin/user_form.html

@@ -1,10 +1,10 @@
 {{define "admin_user_form"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>{{if .isEdit}}编辑用户{{else}}新增用户{{end}} - MailGo</title>
+    <title>{{if .isEdit}}{{t .Lang "编辑用户"}}{{else}}{{t .Lang "新增用户"}}{{end}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,58 +12,67 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
-                    <h2 style="margin-bottom:16px;">{{if .isEdit}}编辑用户{{else}}新增用户{{end}}</h2>
+                    <h2 style="margin-bottom:16px;">{{if .isEdit}}{{t .Lang "编辑用户"}}{{else}}{{t .Lang "新增用户"}}{{end}}</h2>
                     {{if .error}}<div class="alert alert-error">{{.error}}</div>{{end}}
                     <form method="POST" action="{{if .isEdit}}/admin/users/{{.user.ID}}{{else}}/admin/users{{end}}">
                         <div class="form-group">
-                            <label>用户名</label>
+                            <label>{{t .Lang "用户名"}}</label>
                             <input type="text" name="username" required value="{{.user.Username}}" placeholder="username">
                         </div>
                         <div class="form-group">
-                            <label>{{if .isEdit}}新密码（留空则不修改）{{else}}密码{{end}}</label>
+                            <label>{{if .isEdit}}{{t .Lang "新密码（留空则不修改）"}}{{else}}{{t .Lang "密码"}}{{end}}</label>
-                            <input type="password" name="password" {{if not .isEdit}}required{{end}} placeholder="请输入密码">
+                            <input type="password" name="password" {{if not .isEdit}}required{{end}} placeholder="{{t .Lang "请输入密码"}}">
                         </div>
                         <div class="form-group">
-                            <label>域名</label>
+                            <label>{{t .Lang "界面语言"}}</label>
+                            <select name="language">
+                                <option value="auto" {{if eq .user.Language "auto"}}selected{{end}}>{{t .Lang "自动（跟随浏览器）"}}</option>
+                                <option value="en" {{if eq .user.Language "en"}}selected{{end}}>English</option>
+                                <option value="zh" {{if eq .user.Language "zh"}}selected{{end}}>中文</option>
+                                <option value="ja" {{if eq .user.Language "ja"}}selected{{end}}>日本語</option>
+                            </select>
+                        </div>
+                        <div class="form-group">
+                            <label>{{t .Lang "域名"}}</label>
                             <select name="domain_id" required>
-                                <option value="">请选择域名</option>
+                                <option value="">{{t .Lang "请选择域名"}}</option>
                                 {{range .domains}}
                                 <option value="{{.ID}}" {{if eq .ID $.user.DomainID}}selected{{end}}>{{.Name}}</option>
                                 {{end}}
                             </select>
                         </div>
                         <div class="form-group">
-                            <label>配额 (GB)</label>
+                            <label>{{t .Lang "配额 (GB)"}}</label>
                             <input type="number" name="quota_gb" min="1" value="5" placeholder="5">
                         </div>
                         <div class="form-group">
                             <label>
                                 <input type="checkbox" name="is_admin" {{if .user.IsAdmin}}checked{{end}}>
-                                管理员
+                                {{t .Lang "管理员"}}
                             </label>
                         </div>
                         {{if .isEdit}}
                         <div class="form-group">
                             <label>
                                 <input type="checkbox" name="is_active" {{if .user.IsActive}}checked{{end}}>
-                                启用账户
+                                {{t .Lang "启用账户"}}
                             </label>
                         </div>
                         {{end}}
-                        <button type="submit" class="btn btn-primary">{{if .isEdit}}保存更改{{else}}创建用户{{end}}</button>
+                        <button type="submit" class="btn btn-primary">{{if .isEdit}}{{t .Lang "保存更改"}}{{else}}{{t .Lang "创建用户"}}{{end}}</button>
-                        <a href="/admin/users" class="btn" style="margin-left:8px;background:#bdc3c7;color:#fff;">取消</a>
+                        <a href="/admin/users" class="btn" style="margin-left:8px;background:#bdc3c7;color:#fff;">{{t .Lang "取消"}}</a>
                     </form>
                 </div>
             </div>

internal/web/templates/admin/users.html

@@ -1,10 +1,10 @@
 {{define "admin_users"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>用户管理 - MailGo</title>
+    <title>{{t .Lang "用户管理"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body>
@@ -12,36 +12,36 @@
     <div class="container">
         <div class="clearfix">
             <div class="sidebar">
-                <a href="/inbox">返回邮箱</a>
+                <a href="/inbox">{{t .Lang "返回邮箱"}}</a>
-                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>控制面板</a>
+                <a href="/admin" {{if eq .activeFolder "admin"}}class="active"{{end}}>{{t .Lang "控制面板"}}</a>
-                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>域名管理</a>
+                <a href="/admin/domains" {{if eq .activeFolder "domains"}}class="active"{{end}}>{{t .Lang "域名管理"}}</a>
-                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>用户管理</a>
+                <a href="/admin/users" {{if eq .activeFolder "users"}}class="active"{{end}}>{{t .Lang "用户管理"}}</a>
-                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>所有邮件</a>
+                <a href="/admin/mails" {{if eq .activeFolder "mails"}}class="active"{{end}}>{{t .Lang "所有邮件"}}</a>
-                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>外发队列</a>
+                <a href="/admin/outbound" {{if eq .activeFolder "outbound"}}class="active"{{end}}>{{t .Lang "外发队列"}}</a>
-                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>协议日志</a>
+                                <a href="/admin/protocol-logs" {{if eq .activeFolder "protocol-logs"}}class="active"{{end}}>{{t .Lang "协议日志"}}</a>
-                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>当前连接</a>
+                <a href="/admin/connections" {{if eq .activeFolder "connections"}}class="active"{{end}}>{{t .Lang "当前连接"}}</a>
-<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>IP黑名单</a>
+<a href="/admin/bans" {{if eq .activeFolder "bans"}}class="active"{{end}}>{{t .Lang "IP黑名单"}}</a>
             </div>
             <div class="content">
                 <div class="card">
                     <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;">
-                        <h2>用户列表</h2>
+                        <h2>{{t .Lang "用户列表"}}</h2>
-                        <a href="/admin/users/new" class="btn btn-primary">新增用户</a>
+                        <a href="/admin/users/new" class="btn btn-primary">{{t .Lang "新增用户"}}</a>
                     </div>
                     {{if not .users}}
-                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">暂无用户</p>
+                    <p style="color:#7f8c8d;text-align:center;padding:40px 0;">{{t $.Lang "暂无用户"}}</p>
                     {{else}}
                     <table>
                         <thead>
                             <tr>
                                 <th>ID</th>
-                                <th>用户名</th>
+                                <th>{{t $.Lang "用户名"}}</th>
-                                <th>域名ID</th>
+                                <th>{{t $.Lang "域名ID"}}</th>
-                                <th>配额</th>
+                                <th>{{t $.Lang "配额"}}</th>
-                                <th>已用</th>
+                                <th>{{t $.Lang "已用"}}</th>
-                                <th>状态</th>
+                                <th>{{t $.Lang "状态"}}</th>
-                                <th>管理员</th>
+                                <th>{{t $.Lang "管理员"}}</th>
-                                <th>操作</th>
+                                <th>{{t $.Lang "操作"}}</th>
                             </tr>
                         </thead>
                         <tbody>
@@ -55,10 +55,10 @@
                                 <td>{{if .IsActive}}✅{{else}}❌{{end}}</td>
                                 <td>{{if .IsAdmin}}✅{{else}}—{{end}}</td>
                                 <td>
-                                    <a href="/admin/users/{{.ID}}/edit" class="btn btn-primary btn-sm">编辑</a>
+                                    <a href="/admin/users/{{.ID}}/edit" class="btn btn-primary btn-sm">{{t $.Lang "编辑"}}</a>
                                     <form method="POST" action="/admin/users/{{.ID}}/delete" style="display:inline;"
-                                          onsubmit="return confirm('确定要删除用户 {{.Username}} 吗？');">
+                                          onsubmit="return confirm('{{tf $.Lang "确定要删除用户 %s 吗？" .Username}}');">
-                                        <button type="submit" class="btn btn-danger btn-sm">删除</button>
+                                        <button type="submit" class="btn btn-danger btn-sm">{{t $.Lang "删除"}}</button>
                                     </form>
                                 </td>
                             </tr>
@@ -70,11 +70,11 @@
                 {{if .totalPages}}
                 <div class="pagination">
                     {{if gt .page 1}}
-                    <a href="/admin/users?page={{sub .page 1}}">上一页</a>
+                    <a href="/admin/users?page={{sub .page 1}}">{{t $.Lang "上一页"}}</a>
                     {{end}}
-                    <span>第 {{.page}} / {{.totalPages}} 页</span>
+                    <span>{{tf $.Lang "第 %d / %d 页" .page .totalPages}}</span>
                     {{if lt .page .totalPages}}
-                    <a href="/admin/users?page={{add .page 1}}">下一页</a>
+                    <a href="/admin/users?page={{add .page 1}}">{{t $.Lang "下一页"}}</a>
                     {{end}}
                 </div>
                 {{end}}

internal/web/templates/banned.html

@@ -1,10 +1,10 @@
 {{define "banned"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>访问被禁止 - MailGo</title>
+    <title>{{t .Lang "访问被禁止"}} - MailGo</title>
     <style>
         * { margin: 0; padding: 0; box-sizing: border-box; }
         body {
@@ -43,34 +43,34 @@
 <body>
     <div class="banned-card">
         <div class="banned-icon">🚫</div>
-        <h1>您的 IP 已被暂时禁止访问</h1>
+        <h1>{{t .Lang "您的 IP 已被暂时禁止访问"}}</h1>
-        <p>由于登录失败次数过多，您的 IP 地址已被暂时封禁。</p>
+        <p>{{t .Lang "由于登录失败次数过多，您的 IP 地址已被暂时封禁。"}}</p>
         {{if .entry}}
         <div class="detail">
             <div class="detail-row">
-                <span class="detail-label">IP 地址</span>
+                <span class="detail-label">{{t .Lang "IP 地址"}}</span>
                 <span class="detail-value">{{.entry.IPAddress}}</span>
             </div>
             <div class="detail-row">
-                <span class="detail-label">封禁档位</span>
+                <span class="detail-label">{{t .Lang "封禁档位"}}</span>
-                <span class="detail-value">{{if gt .entry.BanCount 3}}第 {{sub .entry.BanCount 3}} 次封禁{{else}}—{{end}}</span>
+                <span class="detail-value">{{if gt .entry.BanCount 3}}{{tf .Lang "第 %d 次封禁" (sub .entry.BanCount 3)}}{{else}}—{{end}}</span>
             </div>
             <div class="detail-row">
-                <span class="detail-label">原因</span>
+                <span class="detail-label">{{t .Lang "原因"}}</span>
-                <span class="detail-value">{{.entry.Reason}}</span>
+                <span class="detail-value">{{t .Lang .entry.Reason}}</span>
             </div>
             <div class="detail-row">
-                <span class="detail-label">失败次数</span>
+                <span class="detail-label">{{t .Lang "失败次数"}}</span>
-                <span class="detail-value">{{.entry.FailCount}} 次</span>
+                <span class="detail-value">{{tf .Lang "%d 次" .entry.FailCount}}</span>
             </div>
             <div class="detail-row">
-                <span class="detail-label">解封时间</span>
+                <span class="detail-label">{{t .Lang "解封时间"}}</span>
-                <span class="detail-value">{{time12 .entry.ExpiresAt}}</span>
+                <span class="detail-value">{{time12 .Lang .entry.ExpiresAt}}</span>
             </div>
         </div>
         {{end}}
-        <p style="font-size:13px;">请在解封时间后重试，或联系管理员。</p>
+        <p style="font-size:13px;">{{t .Lang "请在解封时间后重试，或联系管理员。"}}</p>
-        <a href="/login" class="back-link">返回登录页</a>
+        <a href="/login" class="back-link">{{t .Lang "返回登录页"}}</a>
     </div>
 </body>
 </html>

internal/web/templates/base.html

@@ -433,22 +433,22 @@
     <div class="topbar-left">
         <a class="logo" href="/inbox">
             <span class="logo-icon">✉</span>
-            <span class="logo-text">MailGo<em>邮箱</em></span>
+            <span class="logo-text">MailGo<em>{{t .Lang "邮箱"}}</em></span>
         </a>
     </div>
     <div class="topbar-search">
         <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/></svg>
-        <input id="mail-search" type="text" placeholder="搜索邮件（发件人 / 主题）" autocomplete="off">
+        <input id="mail-search" type="text" placeholder="{{t .Lang "搜索邮件（发件人 / 主题）"}}" autocomplete="off">
     </div>
     <div class="topbar-right">
-        {{if .currentUser.IsAdmin}}<a class="topbar-link" href="/admin">管理后台</a>{{end}}
+        {{if .currentUser.IsAdmin}}<a class="topbar-link" href="/admin">{{t .Lang "管理后台"}}</a>{{end}}
-        <a class="topbar-link" href="/settings">设置</a>
+        <a class="topbar-link" href="/settings">{{t .Lang "设置"}}</a>
         <span class="user-chip">
             <span class="avatar avatar-sm" style="{{avatarStyle .currentUser.Username}}">{{initial .currentUser.Username}}</span>
             <span class="user-email" title="{{.currentUser.Username}}@{{.currentUser.Domain.Name}}">{{.currentUser.Username}}@{{.currentUser.Domain.Name}}</span>
         </span>
         <form method="POST" action="/logout" class="logout-form">
-            <button type="submit" class="icon-btn" title="退出登录">
+            <button type="submit" class="icon-btn" title="{{t .Lang "退出登录"}}">
                 <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4"/><polyline points="16 17 21 12 16 7"/><line x1="21" y1="12" x2="9" y2="12"/></svg>
             </button>
         </form>
@@ -461,7 +461,7 @@
 <aside class="mail-sidebar">
     <a href="/compose" class="compose-btn">
         <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M11 4H4a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2v-7"/><path d="M18.5 2.5a2.121 2.121 0 0 1 3 3L12 15l-4 1 1-4 9.5-9.5z"/></svg>
-        写信
+        {{t .Lang "写信"}}
     </a>
     <nav class="folder-nav">
         {{range .folders}}
@@ -477,7 +477,7 @@
             {{else}}
             <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z"/></svg>
             {{end}}
-            {{folderLabel .Name}}
+            {{folderLabel $.Lang .Name}}
             {{if eq .Name "INBOX"}}
             {{if .Unseen}}<span class="badge">{{.Unseen}}</span>{{end}}
             {{else if .Total}}<span class="count">{{.Total}}</span>{{end}}
@@ -488,7 +488,7 @@
         {{if .currentUser.IsAdmin}}
         <a class="folder" href="/admin">
             <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z"/></svg>
-            管理后台
+            {{t .Lang "管理后台"}}
         </a>
         {{end}}
     </div>
@@ -541,7 +541,7 @@
         var ids = rows.filter(function (r) { return r.isConnected && r.querySelector('.row-check').checked; })
                       .map(function (r) { return r.dataset.id; });
         if (!ids.length) return;
-        if (!confirm('确定要删除选中的 ' + ids.length + ' 封邮件吗？')) return;
+        if (!confirm('{{t .Lang "确定要删除选中的 %s 封邮件吗？"}}'.replace('%s', ids.length))) return;
         var done = 0;
         ids.forEach(function (id) {
             fetch('/mail/delete/' + id, { method: 'POST', body: new FormData() })

internal/web/templates/compose.html

@@ -1,10 +1,10 @@
 {{define "compose"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>写信 - MailGo</title>
+    <title>{{t .Lang "写信"}} - MailGo</title>
     <link href="/static/vendor/quill/quill.snow.css" rel="stylesheet">
     {{template "styles" .}}
 </head>
@@ -16,44 +16,44 @@
             <div class="compose-toolbar">
                 <button type="submit" form="compose-form" class="btn btn-primary">
                     <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px;margin-right:4px;"><line x1="22" y1="2" x2="11" y2="13"/><polygon points="22 2 15 22 11 13 2 9 22 2"/></svg>
-                    发送
+                    {{t .Lang "发送"}}
                 </button>
                 <label class="tb-btn" style="cursor:pointer;">
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21.44 11.05l-9.19 9.19a6 6 0 0 1-8.49-8.49l9.19-9.19a4 4 0 0 1 5.66 5.66l-9.2 9.19a2 2 0 0 1-2.83-2.83l8.49-8.48"/></svg>
-                    附件
+                    {{t .Lang "附件"}}
                     <input type="file" name="attachments" id="attach-input" multiple style="display:none;">
                 </label>
-                <a href="/inbox" class="tb-btn">取消</a>
+                <a href="/inbox" class="tb-btn">{{t .Lang "取消"}}</a>
                 <div class="toolbar-spacer"></div>
-                <span class="page-info">撰写新邮件</span>
+                <span class="page-info">{{t .Lang "撰写新邮件"}}</span>
             </div>
 
             {{if .error}}<div class="alert alert-error" style="margin:12px 18px 0;">{{.error}}</div>{{end}}
 
             <form id="compose-form" class="compose-form" method="POST" action="/compose" enctype="multipart/form-data">
                 <div class="compose-field">
-                    <label>收件人</label>
+                    <label>{{t .Lang "收件人"}}</label>
-                    <input type="email" name="to" required value="{{.to}}" placeholder="输入收件人邮箱地址">
+                    <input type="email" name="to" required value="{{.to}}" placeholder="{{t .Lang "输入收件人邮箱地址"}}">
                 </div>
                 <div class="compose-field">
-                    <label>抄送</label>
+                    <label>{{t .Lang "抄送"}}</label>
-                    <input type="text" name="cc" value="{{.cc}}" placeholder="多个地址用逗号分隔（可选）">
+                    <input type="text" name="cc" value="{{.cc}}" placeholder="{{t .Lang "多个地址用逗号分隔（可选）"}}">
                 </div>
                 <div class="compose-field">
-                    <label>主题</label>
+                    <label>{{t .Lang "主题"}}</label>
-                    <input type="text" name="subject" value="{{.subject}}" placeholder="输入邮件主题">
+                    <input type="text" name="subject" value="{{.subject}}" placeholder="{{t .Lang "输入邮件主题"}}">
                 </div>
 
                 <div id="attach-chips" class="attach-chips" style="{{if not .attachments}}display:none;{{end}}"></div>
 
                 <div class="editor-wrap">
-                    <div id="editor" data-placeholder="请输入邮件内容..."></div>
+                    <div id="editor" data-placeholder="{{t .Lang "请输入邮件内容..."}}"></div>
                     <input type="hidden" name="body" id="body-hidden">
                     <input type="hidden" name="html_body" id="html-body-hidden">
                 </div>
 
                 <div class="compose-footer">
-                    <span>附件配额</span>
+                    <span>{{t .Lang "附件配额"}}</span>
                     <span class="quota-bar" id="quota-bar" data-used="{{.usedBytes}}" data-quota="{{.quotaBytes}}"><i></i></span>
                     <span id="quota-text">{{formatBytes .usedBytes}} / {{formatBytes .quotaBytes}}</span>
                 </div>
@@ -64,7 +64,7 @@
     <script>
     var quill = new Quill('#editor', {
         theme: 'snow',
-        placeholder: document.getElementById('editor').dataset.placeholder || '请输入邮件内容...',
+        placeholder: document.getElementById('editor').dataset.placeholder || '{{t .Lang "请输入邮件内容..."}}',
         modules: {
             toolbar: [
                 [{ 'header': [1, 2, 3, false] }],
@@ -96,7 +96,7 @@
             var chip = document.createElement('span');
             chip.className = 'attach-chip';
             chip.innerHTML = '📎 ' + f.name + ' (' + (f.size / 1024).toFixed(1) + ' KB)' +
-                '<button type="button" class="chip-del" data-i="' + i + '" title="移除">✕</button>';
+                '<button type="button" class="chip-del" data-i="' + i + '" title="{{t .Lang "移除"}}">✕</button>';
             chipsBox.appendChild(chip);
         });
     }

internal/web/templates/folder.html

@@ -1,10 +1,10 @@
 {{define "folder"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>{{folderLabel .folder}} - MailGo</title>
+    <title>{{folderLabel .Lang .folder}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body class="page-list">
@@ -13,31 +13,31 @@
         {{template "sidebar" .}}
         <main class="mail-main">
             <div class="list-toolbar">
-                <label class="check-all" title="全选/取消全选">
+                <label class="check-all" title="{{t .Lang "全选/取消全选"}}">
                     <input type="checkbox" id="select-all">
-                    全选
+                    {{t .Lang "全选"}}
                 </label>
-                <button type="button" class="tb-btn" id="btn-refresh" title="刷新">
+                <button type="button" class="tb-btn" id="btn-refresh" title="{{t .Lang "刷新"}}">
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="23 4 23 10 17 10"/><path d="M20.49 15a9 9 0 1 1-2.12-9.36L23 10"/></svg>
-                    刷新
+                    {{t .Lang "刷新"}}
                 </button>
                 <button type="button" class="tb-btn danger" id="btn-delete" disabled>
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
-                    {{if .isTrash}}彻底删除{{else}}删除{{end}}
+                    {{if .isTrash}}{{t $.Lang "彻底删除"}}{{else}}{{t $.Lang "删除"}}{{end}}
                 </button>
                 {{if .isTrash}}
                 <form method="POST" action="/folder/Trash/empty" style="display:inline;"
-                      onsubmit="return confirm('确定要清空「已删除」文件夹吗？此操作不可恢复。');">
+                      onsubmit="return confirm('{{t $.Lang "确定要清空「已删除」文件夹吗？此操作不可恢复。"}}');">
-                    <button type="submit" class="tb-btn danger">清空文件夹</button>
+                    <button type="submit" class="tb-btn danger">{{t $.Lang "清空文件夹"}}</button>
                 </form>
                 {{end}}
                 <div class="toolbar-spacer"></div>
-                <span class="page-info">共 {{.total}} 封</span>
+                <span class="page-info">{{tf .Lang "共 %d 封" .total}}</span>
             </div>
 
             {{if not .messages}}
             <div class="mail-list">
-                <div class="empty-tip"><span class="empty-icon">{{if .isTrash}}🗑{{else}}📭{{end}}</span>{{folderLabel .folder}}暂无邮件</div>
+                <div class="empty-tip"><span class="empty-icon">{{if .isTrash}}🗑{{else}}📭{{end}}</span>{{folderLabel $.Lang $.folder}} · {{t $.Lang "暂无邮件"}}</div>
             </div>
             {{else}}
             <ul class="mail-list">
@@ -53,9 +53,9 @@
                         <span class="avatar" style="{{avatarStyle .FromAddr}}">{{initial (mailName (decodeHeader .FromAddr))}}</span>
                         {{end}}
                     </span>
-                    <span class="cell-from" {{if or (eq $.folder "Sent") (eq $.folder "Drafts")}}title="收件人：{{.ToAddr}}"{{else}}title="{{decodeHeader .FromAddr}}"{{end}}>
+                    <span class="cell-from" {{if or (eq $.folder "Sent") (eq $.folder "Drafts")}}title="{{tf $.Lang "收件人：%s" .ToAddr}}"{{else}}title="{{decodeHeader .FromAddr}}"{{end}}>
                         {{if or (eq $.folder "Sent") (eq $.folder "Drafts")}}
-                        {{if eq $.folder "Drafts"}}致：{{end}}{{mailName .ToAddr}}
+                        {{if eq $.folder "Drafts"}}{{t $.Lang "致："}}{{end}}{{mailName .ToAddr}}
                         {{else}}
                         {{mailName (decodeHeader .FromAddr)}}
                         {{end}}
@@ -63,24 +63,24 @@
                     <span class="cell-subject-wrap">
                         {{if not .IsRead}}<span class="unread-dot"></span>{{end}}
                         <a class="cell-subject" href="/folder/{{urlPath $.folder}}/{{.ID}}">
-                            {{if .Subject}}{{.Subject}}{{else}}(无主题){{end}}
+                            {{if .Subject}}{{.Subject}}{{else}}{{t $.Lang "(无主题)"}}{{end}}
                         </a>
                     </span>
                     <span class="cell-snippet">
-                        {{if .TextBody}}{{truncate .TextBody 80}}{{else if .HtmlBody}}[HTML 邮件]{{end}}
+                        {{if .TextBody}}{{truncate .TextBody 80}}{{else if .HtmlBody}}{{t $.Lang "[HTML 邮件]"}}{{end}}
                     </span>
-                    <span class="cell-date">{{shortDate .Date}}</span>
+                    <span class="cell-date">{{shortDate $.Lang .Date}}</span>
                     {{if $.isTrash}}
                     <form method="POST" action="/mail/restore/{{.ID}}" class="row-del"
-                          onsubmit="event.stopPropagation(); return confirm('确定要恢复这封邮件吗？');">
+                          onsubmit="event.stopPropagation(); return confirm('{{t $.Lang "确定要恢复这封邮件吗？"}}');">
-                        <button type="submit" class="icon-btn" title="恢复到收件箱">
+                        <button type="submit" class="icon-btn" title="{{t $.Lang "恢复到收件箱"}}">
                             <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="1 4 1 10 7 10"/><path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10"/></svg>
                         </button>
                     </form>
                     {{else}}
                     <form method="POST" action="/mail/delete/{{.ID}}" class="row-del"
-                          onsubmit="event.stopPropagation(); return confirm('确定要删除这封邮件吗？');">
+                          onsubmit="event.stopPropagation(); return confirm('{{t $.Lang "确定要删除这封邮件吗？"}}');">
-                        <button type="submit" class="icon-btn" title="删除">
+                        <button type="submit" class="icon-btn" title="{{t $.Lang "删除"}}">
                             <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
                         </button>
                     </form>
@@ -91,23 +91,23 @@
             {{end}}
 
             <div class="list-footer">
-                <span class="page-num">第 {{.page}} / {{if .totalPages}}{{.totalPages}}{{else}}1{{end}} 页</span>
+                <span class="page-num">{{tf .Lang "第 %d / %d 页" .page (or .totalPages 1)}}</span>
                 <div class="pager">
                     {{if gt .page 1}}
                     <a class="page-btn" href="/folder/{{urlPath .folder}}?page={{sub .page 1}}">
                         <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="15 18 9 12 15 6"/></svg>
-                        上一页
+                        {{t $.Lang "上一页"}}
                     </a>
                     {{else}}
-                    <span class="page-btn disabled">上一页</span>
+                    <span class="page-btn disabled">{{t $.Lang "上一页"}}</span>
                     {{end}}
                     {{if lt .page .totalPages}}
                     <a class="page-btn" href="/folder/{{urlPath .folder}}?page={{add .page 1}}">
-                        下一页
+                        {{t $.Lang "下一页"}}
                         <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 18 15 12 9 6"/></svg>
                     </a>
                     {{else}}
-                    <span class="page-btn disabled">下一页</span>
+                    <span class="page-btn disabled">{{t $.Lang "下一页"}}</span>
                     {{end}}
                 </div>
             </div>

internal/web/templates/login.html

@@ -1,55 +1,55 @@
 {{define "login"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>登录 - MailGo 邮箱</title>
+    <title>{{t .Lang "登录"}} - MailGo {{t .Lang "邮箱"}}</title>
     {{template "styles" .}}
 </head>
 <body class="login-page">
     <div class="login-card">
         <div class="login-logo">
             <span class="logo-icon" style="width:44px;height:44px;font-size:22px;border-radius:12px;">✉</span>
-            <span style="font-size:26px;font-weight:700;color:var(--primary);">MailGo<em style="font-style:normal;font-weight:400;font-size:15px;color:var(--text-2);margin-left:4px;">邮箱</em></span>
+            <span style="font-size:26px;font-weight:700;color:var(--primary);">MailGo<em style="font-style:normal;font-weight:400;font-size:15px;color:var(--text-2);margin-left:4px;">{{t .Lang "邮箱"}}</em></span>
         </div>
-        <div class="login-sub">登录您的邮箱账户</div>
+        <div class="login-sub">{{t .Lang "登录您的邮箱账户"}}</div>
 
         {{if .error}}<div class="alert alert-error">{{.error}}</div>{{end}}
 
         <form method="POST" action="/login">
             <div class="form-group">
-                <label>邮箱地址</label>
+                <label>{{t .Lang "邮箱地址"}}</label>
                 <input type="email" name="email" required autofocus placeholder="user@example.com" style="padding:11px 14px;border-radius:8px;">
             </div>
             <div class="form-group">
-                <label>密码</label>
+                <label>{{t .Lang "密码"}}</label>
-                <input type="password" name="password" required placeholder="请输入密码" style="padding:11px 14px;border-radius:8px;">
+                <input type="password" name="password" required placeholder="{{t .Lang "请输入密码"}}" style="padding:11px 14px;border-radius:8px;">
             </div>
-            <button type="submit" class="btn btn-primary" style="width:100%;padding:11px 16px;font-size:15px;border-radius:8px;">登 录</button>
+            <button type="submit" class="btn btn-primary" style="width:100%;padding:11px 16px;font-size:15px;border-radius:8px;">{{t .Lang "登 录"}}</button>
         </form>
 
         {{if or .oauth2Enabled .ldapEnabled}}
-        <div class="divider">或</div>
+        <div class="divider">{{t .Lang "或"}}</div>
         {{end}}
 
         {{if .ldapEnabled}}
         <form method="POST" action="/login/ldap" style="margin-bottom:10px;">
             <div class="form-group">
-                <label>LDAP 用户名</label>
+                <label>{{t .Lang "LDAP 用户名"}}</label>
-                <input type="text" name="username" placeholder="LDAP 用户名">
+                <input type="text" name="username" placeholder="{{t .Lang "LDAP 用户名"}}">
             </div>
             <div class="form-group">
-                <label>LDAP 密码</label>
+                <label>{{t .Lang "LDAP 密码"}}</label>
-                <input type="password" name="password" placeholder="LDAP 密码">
+                <input type="password" name="password" placeholder="{{t .Lang "LDAP 密码"}}">
             </div>
-            <button type="submit" class="btn" style="width:100%;background:#7b5cd6;color:#fff;">LDAP 登录</button>
+            <button type="submit" class="btn" style="width:100%;background:#7b5cd6;color:#fff;">{{t .Lang "LDAP 登录"}}</button>
         </form>
         {{end}}
 
         {{if .oauth2Enabled}}
         <a href="/auth/oauth2" class="btn btn-primary" style="width:100%;text-align:center;display:block;margin-top:4px;">
-            {{if eq .oauth2Provider "google"}}Google{{else if eq .oauth2Provider "github"}}GitHub{{else}}OAuth2{{end}} 登录
+            {{if eq .oauth2Provider "google"}}Google{{else if eq .oauth2Provider "github"}}GitHub{{else}}OAuth2{{end}} {{t .Lang "登录"}}
         </a>
         {{end}}
     </div>

internal/web/templates/settings.html

@@ -1,10 +1,10 @@
 {{define "settings"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>设置 - MailGo</title>
+    <title>{{t .Lang "设置"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body class="page-settings">
@@ -15,21 +15,21 @@
             {{if .error}}<div class="alert alert-error">{{.error}}</div>{{end}}
             {{if .success}}<div class="alert alert-success">{{.success}}</div>{{end}}
             {{if .mustChange}}<div class="alert" style="border:1px solid #ffa940;background:#fff7e6;color:#d46b08;border-radius:8px;padding:12px 16px;margin-bottom:16px;font-size:13.5px;">
-                ⚠️ 首次登录/密码已被重置，请立即修改密码后再继续使用邮箱功能。
+                {{t .Lang "⚠️ 首次登录/密码已被重置，请立即修改密码后再继续使用邮箱功能。"}}
             </div>{{end}}
 
             <div class="card" style="max-width:720px;">
                 <h2 style="font-size:17px;margin-bottom:18px;display:flex;align-items:center;gap:10px;">
                     <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="#1677ff" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="3"/><path d="M19.4 15a1.65 1.65 0 0 0 .33 1.82l.06.06a2 2 0 0 1 0 2.83 2 2 0 0 1-2.83 0l-.06-.06a1.65 1.65 0 0 0-1.82-.33 1.65 1.65 0 0 0-1 1.51V21a2 2 0 0 1-2 2 2 2 0 0 1-2-2v-.09A1.65 1.65 0 0 0 9 19.4a1.65 1.65 0 0 0-1.82.33l-.06.06a2 2 0 0 1-2.83 0 2 2 0 0 1 0-2.83l.06-.06a1.65 1.65 0 0 0 .33-1.82 1.65 1.65 0 0 0-1.51-1H3a2 2 0 0 1-2-2 2 2 0 0 1 2-2h.09A1.65 1.65 0 0 0 4.6 9a1.65 1.65 0 0 0-.33-1.82l-.06-.06a2 2 0 0 1 0-2.83 2 2 0 0 1 2.83 0l.06.06a1.65 1.65 0 0 0 1.82.33H9a1.65 1.65 0 0 0 1-1.51V3a2 2 0 0 1 2-2 2 2 0 0 1 2 2v.09a1.65 1.65 0 0 0 1 1.51 1.65 1.65 0 0 0 1.82-.33l.06-.06a2 2 0 0 1 2.83 0 2 2 0 0 1 0 2.83l-.06.06a1.65 1.65 0 0 0-.33 1.82V9a1.65 1.65 0 0 0 1.51 1H21a2 2 0 0 1 2 2 2 2 0 0 1-2 2h-.09a1.65 1.65 0 0 0-1.51 1z"/></svg>
-                    账号信息
+                    {{t .Lang "账号信息"}}
                 </h2>
                 <div style="display:flex;align-items:center;gap:14px;margin-bottom:20px;">
                     <span class="avatar" style="width:52px;height:52px;font-size:22px;{{avatarStyle .currentUser.Username}}">{{initial .currentUser.Username}}</span>
                     <div>
                         <div style="font-size:16px;font-weight:600;">{{.currentUser.Username}}@{{.currentUser.Domain.Name}}</div>
                         <div style="color:var(--text-3);font-size:12.5px;margin-top:3px;">
-                            已用 {{formatBytes .currentUser.UsedBytes}} / 配额 {{formatBytes .currentUser.QuotaBytes}}
+                            {{tf .Lang "已用 %s / 配额 %s" (formatBytes .currentUser.UsedBytes) (formatBytes .currentUser.QuotaBytes)}}
-                            {{if .currentUser.IsAdmin}} · 管理员{{end}}
+                            {{if .currentUser.IsAdmin}} · {{t .Lang "管理员"}}{{end}}
                         </div>
                     </div>
                 </div>
@@ -37,30 +37,46 @@
             </div>
 
             <div class="card" style="max-width:720px;">
-                <h2 style="font-size:17px;margin-bottom:18px;">修改密码</h2>
+                <h2 style="font-size:17px;margin-bottom:18px;">{{t .Lang "界面语言"}}</h2>
                 <form method="POST" action="/settings" style="max-width:420px;">
                     <div class="form-group">
-                        <label>当前密码</label>
+                        <label>{{t .Lang "界面语言"}}</label>
-                        <input type="password" name="old_password" required placeholder="请输入当前密码" autocomplete="current-password">
+                        <select name="language">
+                            <option value="auto" {{if eq .currentUser.Language "auto"}}selected{{end}}>{{t .Lang "自动（跟随浏览器）"}}</option>
+                            <option value="en" {{if eq .currentUser.Language "en"}}selected{{end}}>English</option>
+                            <option value="zh" {{if eq .currentUser.Language "zh"}}selected{{end}}>中文</option>
+                            <option value="ja" {{if eq .currentUser.Language "ja"}}selected{{end}}>日本語</option>
+                        </select>
                     </div>
-                    <div class="form-group">
+                    <button type="submit" class="btn btn-primary">{{t .Lang "保存"}}</button>
-                        <label>新密码</label>
-                        <input type="password" name="new_password" required placeholder="请输入新密码" autocomplete="new-password">
-                    </div>
-                    <div class="form-group">
-                        <label>确认新密码</label>
-                        <input type="password" name="confirm_password" required placeholder="请再次输入新密码" autocomplete="new-password">
-                    </div>
-                    <button type="submit" class="btn btn-primary">修改密码</button>
                 </form>
             </div>
 
             <div class="card" style="max-width:720px;">
-                <h2 style="font-size:17px;margin-bottom:10px;">帮助</h2>
+                <h2 style="font-size:17px;margin-bottom:18px;">{{t .Lang "修改密码"}}</h2>
+                <form method="POST" action="/settings" style="max-width:420px;">
+                    <div class="form-group">
+                        <label>{{t .Lang "当前密码"}}</label>
+                        <input type="password" name="old_password" required placeholder="{{t .Lang "请输入当前密码"}}" autocomplete="current-password">
+                    </div>
+                    <div class="form-group">
+                        <label>{{t .Lang "新密码"}}</label>
+                        <input type="password" name="new_password" required placeholder="{{t .Lang "请输入新密码"}}" autocomplete="new-password">
+                    </div>
+                    <div class="form-group">
+                        <label>{{t .Lang "确认新密码"}}</label>
+                        <input type="password" name="confirm_password" required placeholder="{{t .Lang "请再次输入新密码"}}" autocomplete="new-password">
+                    </div>
+                    <button type="submit" class="btn btn-primary">{{t .Lang "修改密码"}}</button>
+                </form>
+            </div>
+
+            <div class="card" style="max-width:720px;">
+                <h2 style="font-size:17px;margin-bottom:10px;">{{t .Lang "帮助"}}</h2>
                 <p style="color:var(--text-2);font-size:13.5px;line-height:1.9;">
-                    客户端收发信（IMAP / SMTP）配置：<br>
+                    {{t .Lang "客户端收发信（IMAP / SMTP）配置："}}<br>
-                    IMAP 服务器：{{.currentUser.Domain.Name}} 端口 143 / SSL 993<br>
+                    {{tf .Lang "IMAP 服务器：%s 端口 %d / SSL %d" .currentUser.Domain.Name 143 993}}<br>
-                    SMTP 服务器：{{.currentUser.Domain.Name}} 端口 587（提交）/ SSL 465
+                    {{tf .Lang "SMTP 服务器：%s 端口 %d（提交）/ SSL %d" .currentUser.Domain.Name 587 465}}
                 </p>
             </div>
         </main>

internal/web/templates/view.html

@@ -1,10 +1,10 @@
 {{define "view"}}
 <!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="{{htmlLang .Lang}}">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
-    <title>查看邮件 - MailGo</title>
+    <title>{{t .Lang "查看邮件"}} - MailGo</title>
     {{template "styles" .}}
 </head>
 <body class="page-view">
@@ -15,50 +15,50 @@
             <div class="view-toolbar">
                 <a href="javascript:history.back()" class="tb-btn">
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="19" y1="12" x2="5" y2="12"/><polyline points="12 19 5 12 12 5"/></svg>
-                    返回
+                    {{t .Lang "返回"}}
                 </a>
                 <a href="/compose?to={{mailEmail .message.FromAddr}}&subject={{if .message.Subject}}Re: {{.message.Subject}}{{end}}" class="tb-btn">
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 17 4 12 9 7"/><path d="M20 18v-2a4 4 0 0 0-4-4H4"/></svg>
-                    回复
+                    {{t .Lang "回复"}}
                 </a>
                 {{if .inTrash}}
                 <form method="POST" action="/mail/restore/{{.message.ID}}" style="display:inline;">
                     <button type="submit" class="tb-btn">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="1 4 1 10 7 10"/><path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10"/></svg>
-                        恢复
+                        {{t .Lang "恢复"}}
                     </button>
                 </form>
                 <form method="POST" action="/mail/purge/{{.message.ID}}" style="display:inline;"
-                      onsubmit="return confirm('确定要彻底删除这封邮件吗？此操作不可恢复。');">
+                      onsubmit="return confirm('{{t .Lang "确定要彻底删除这封邮件吗？此操作不可恢复。"}}');">
                     <button type="submit" class="tb-btn danger">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
-                        彻底删除
+                        {{t .Lang "彻底删除"}}
                     </button>
                 </form>
                 {{else}}
                 <form method="POST" action="/mail/delete/{{.message.ID}}" style="display:inline;"
-                      onsubmit="return confirm('确定要删除这封邮件吗？');">
+                      onsubmit="return confirm('{{t .Lang "确定要删除这封邮件吗？"}}');">
                     <button type="submit" class="tb-btn danger">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
-                        删除
+                        {{t .Lang "删除"}}
                     </button>
                 </form>
                 {{end}}
             </div>
 
             <div class="mail-head">
-                <h1 class="mail-title">{{if .message.Subject}}{{.message.Subject}}{{else}}(无主题){{end}}</h1>
+                <h1 class="mail-title">{{if .message.Subject}}{{.message.Subject}}{{else}}{{t .Lang "(无主题)"}}{{end}}</h1>
                 <div class="mail-from-row">
                     <span class="avatar" style="{{avatarStyle .message.FromAddr}}">{{initial (mailName (decodeHeader .message.FromAddr))}}</span>
                     <div>
                         <div class="mail-from-name">{{mailName (decodeHeader .message.FromAddr)}}</div>
                         <div class="mail-from-addr" title="{{decodeHeader .message.FromAddr}}">{{mailEmail .message.FromAddr}}</div>
                     </div>
-                    <span class="mail-date">{{time12 .message.Date}}</span>
+                    <span class="mail-date">{{time12 .Lang .message.Date}}</span>
                 </div>
                 {{if .message.CcAddr}}
                 <div class="mail-from-addr" style="margin:-8px 0 16px 48px;">
-                    抄送：{{.message.CcAddr}}
+                    {{t .Lang "抄送："}}{{.message.CcAddr}}
                 </div>
                 {{end}}
             </div>
@@ -88,28 +88,28 @@
             <div class="view-actions">
                 <a href="/compose?to={{mailEmail .message.FromAddr}}&subject={{if .message.Subject}}Re: {{.message.Subject}}{{end}}" class="btn btn-primary">
                     <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px;margin-right:4px;"><polyline points="9 17 4 12 9 7"/><path d="M20 18v-2a4 4 0 0 0-4-4H4"/></svg>
-                    回复
+                    {{t .Lang "回复"}}
                 </a>
                 {{if .inTrash}}
                 <form method="POST" action="/mail/restore/{{.message.ID}}" style="display:inline;">
                     <button type="submit" class="btn">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px;margin-right:4px;"><polyline points="1 4 1 10 7 10"/><path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10"/></svg>
-                        恢复到收件箱
+                        {{t .Lang "恢复到收件箱"}}
                     </button>
                 </form>
                 <form method="POST" action="/mail/purge/{{.message.ID}}" style="display:inline;"
-                      onsubmit="return confirm('确定要彻底删除这封邮件吗？此操作不可恢复。');">
+                      onsubmit="return confirm('{{t .Lang "确定要彻底删除这封邮件吗？此操作不可恢复。"}}');">
                     <button type="submit" class="btn btn-danger">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px;margin-right:4px;"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
-                        彻底删除
+                        {{t .Lang "彻底删除"}}
                     </button>
                 </form>
                 {{else}}
                 <form method="POST" action="/mail/delete/{{.message.ID}}" style="display:inline;"
-                      onsubmit="return confirm('确定要删除这封邮件吗？');">
+                      onsubmit="return confirm('{{t .Lang "确定要删除这封邮件吗？"}}');">
                     <button type="submit" class="btn btn-danger">
                         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px;margin-right:4px;"><polyline points="3 6 5 6 21 6"/><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"/></svg>
-                        删除邮件
+                        {{t .Lang "删除邮件"}}
                     </button>
                 </form>
                 {{end}}

internal/web/timefmt_test.go

@@ -33,7 +33,7 @@ func TestTime12Format(t *testing.T) {
 		{"凌晨", time.Date(2026, 8, 20, 16, 0, 0, 0, time.UTC), "2026-08-21 上午 12:00:00"},
 	}
 	for _, tc := range cases {
-		if got := time12(tc.in); got != tc.want {
+		if got := time12("zh", tc.in); got != tc.want {
 			t.Errorf("time12(%s) = %q, want %q", tc.name, got, tc.want)
 		}
 	}
@@ -42,7 +42,7 @@ func TestTime12Format(t *testing.T) {
 func TestTime12mNoSeconds(t *testing.T) {
 	setWebTZForTest(t, time.FixedZone("UTC+8", 8*3600))
 	in := time.Date(2026, 8, 20, 10, 30, 45, 0, time.UTC)
-	if got, want := time12m(in), "2026-08-20 下午 6:30"; got != want {
+	if got, want := time12m("zh", in), "2026-08-20 下午 6:30"; got != want {
 		t.Fatalf("time12m = %q, want %q", got, want)
 	}
 }
@@ -53,7 +53,7 @@ func TestShortDate12Hour(t *testing.T) {
 
 	// 今天 → 「下午 2:35」（无日期）
 	today := time.Date(now.Year(), now.Month(), now.Day(), 14, 35, 0, 0, webTZ).UTC()
-	if got, want := shortDate(today), "下午 2:35"; got != want {
+	if got, want := shortDate("zh", today), "下午 2:35"; got != want {
 		t.Fatalf("shortDate(today) = %q, want %q", got, want)
 	}
 
@@ -62,13 +62,13 @@ func TestShortDate12Hour(t *testing.T) {
 	if day.YearDay() == now.YearDay() {
 		day = day.AddDate(0, 0, 1)
 	}
-	if got, want := shortDate(day.UTC()), day.Format("01-02")+" 上午 9:05"; got != want {
+	if got, want := shortDate("zh", day.UTC()), day.Format("01-02")+" 上午 9:05"; got != want {
 		t.Fatalf("shortDate(thisYear) = %q, want %q", got, want)
 	}
 
 	// 往年 → 「YYYY-MM-DD 上午 9:05」
 	older := time.Date(now.Year()-1, 12, 1, 9, 5, 0, 0, webTZ).UTC()
-	if got, want := shortDate(older), fmt.Sprintf("%d-12-01 上午 9:05", now.Year()-1); got != want {
+	if got, want := shortDate("zh", older), fmt.Sprintf("%d-12-01 上午 9:05", now.Year()-1); got != want {
 		t.Fatalf("shortDate(older) = %q, want %q", got, want)
 	}
 }