Reject content that escapes the content root

[serenakeyitan]

A doc I generated rendered full-bleed on tdoc.dev, and every check passed on the way out.

One stray </div> closed .wrap at byte 4189 of a 37KB document. The remaining 89% became siblings of the root, so :where(body > .wrap) — which supplies the 720px column — stopped applying to it. Measured against the previous version at the same viewport:

	content width at 1280px
v2	671px
v4	1261px

Nothing else was wrong. The doc had a content root, its CSS was in contract, its figures were in bounds. The nesting was the only tell, and nothing looked at it.

The check

The parser already counted content roots at body level. It now also records the elements it finds beside one, and rejects them by name and count.

It fires only when a root exists. A doc with no root at all is a supported shape — the template applies the column to body itself through :has() — and its headings are the document rather than escapees. ~/tdocs/hello is exactly that, and it was the one false positive in a sweep of every doc on this machine before that condition went in. Zero after.

<script>, <style>, <template> and <noscript> beside the root are not content and do not trip it.

Tier

Structural, not stylistic, so it runs on both paths — beside the existing "exactly one content root" rule, which would otherwise be trivially satisfiable by a document whose root wraps only its first paragraph.

46 offline suites green; the new test covers the escaped case, the correctly nested case, and a <template> sibling.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Xw9Mt3rV3ujnejPr41pqvz

[github-actions]

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