design/revertible-effects and design/context-model carry real TeX that was
showing as literal $$ source. markdown: { math: true } enables
markdown-it-mathjax3; pinned ^4.3.2 deliberately — v5 injects a <style> tag
per formula (31 on one page), which Vue's template compiler rejects, so v5
cannot work under VitePress; v4 emits pure SVG (probed: 0 style tags).