One-entry outline

This page has a sidebar and a table of contents, and the table of contents holds exactly one entry: Starlight’s synthetic “Overview” row. It carries no headings at all, which is the state TocJump.astro’s flat.length >= 2 gate exists for — a control offering a single choice is chrome, not navigation.

The rendered consequence is what mobile-content.css §D4b’s collapse rule claims: with no jump control drawn, the 3rem --sl-mobile-toc-height slot the frame’s top padding and scroll-padding-top reserve must go to 0rem, or every page like this one wears a band of empty chrome under the header.

Every other fixture page in this corpus renders two or more TOC entries, so without this page the collapse branch could only ever be exercised by moving the DOM around in a test — which proves the CSS selector, never the page. It is kept out of the search index (pagefind: false) so it stays a layout fixture rather than a new answer in the search census.