The toc frontmatter now takes two styles (frontmatter only, not config):
- toc: true (default, unchanged): the ruled contents box, always visible
- toc: disclosure: the same entries as a native /
, collapsed until clicked — the browser toggles it, no JavaScript
- toc: false/0/no/off stay off (backwards compatible); any other value is a hard error, like an unknown type
Post.TOCStyle carries the style; TOCFromHTML takes it as an argument and only changes the wrapper (nav+p.toc__title vs details+summary). The disclosure reuses the .toc ruled-box CSS; a small summary rule matches the title's weight. Post-page, unit and parse tests cover both styles and the error case; the showcase post documents and lists the new option. Default output is byte-identical to before.