Structured Artifact

A structured artifact is plain HTML that opens from file:// and works on a phone. Load /information-hierarchy first — it decides what each page shows and in what order; this skill builds it.

One page or several

Start from one index.html. Its first viewport carries the answer, and depth discloses in place — <details>, popovers, a collapsible detail panel. Grow into a folder (index.html + child pages + shared.css) when readers need whole pages per branch: the index becomes a map with links, and each child page stands alone with its own lede. resources/multi-page-site.md has the folder mechanics.

Build so it keeps working