CSS Cascade 6: an example of overlapping scopes in §3.5.1 does not follow the current definition of scoping limits

The last block of example #example-463550a5 uses to ([data-scope] > *) and says both sections are part of the outer scope. Under §3.5.2 and §3.5.4 the scope end is an ordinary selector list, so both children of the outer section, a p and the inner section, are scoping limits and are out of scope. The example holds only if the scope end is matched relative to :scope, which open issue 13290 proposes; the note was sent there as a comment.

Consequence

With the example's HTML, the current text applies section { background: snow } to no section and p { color: red } to no p; the example says the inner section is styled by both scopes.

Proposed correction

Once issue 13290 is resolved, check the example against the chosen definition, for example by using to (:scope [data-scope] > *).

Issued by

World Wide Web Consortium (W3C) — CSS Working Group

Act

CSS Cascading and Inheritance Level 6 (Editor's Draft, 28 April 2026)

Place

§3.5.1, example #example-463550a5

Record

Discrepancy

Class

Text of the act

Where it arose

The text of the act

Arxo's conclusion

Confirmed

Official text

Unchanged at last check

Last checked

2026-10-31

Evidence

Reproduced by execution. Quotations are verbatim from the official material; translations are ours and marked.

However, authors can use the child combinator and universal selector to create scope boundaries that overlap, such that the inner scope root is part of both scopes:

both sections are part of the outer scope

For each scope created by a scoping root, its scoping limits are set to all elements that are descendants of the scoping root and that match <scope-end>, interpreting :scope and & exactly as in scoped style rules.

It is not an inclusive descendant of a scoping limit.

How to check it without Arxo's tools

1. Open CSS Cascading and Inheritance Level 6, Editor's Draft of 28 April 2026 (W3C CSS Working Group) and find §3.5.1 Effects of @scope, example #example-463550a5; §3.5.4 Scoping Limits; §3.5 Scoped Styles. Compare the text with the quotation above. A copy is kept in this register: 6d3da5b4b2077a16-ed-css-cascade-6.html (SHA-256 6d3da5b4b2077a16b70b1fc38967bca88c41f1f9fd85aba223e4ae2525953e3c, copy of the official file).
2. The finding holds if the quoted passages read as shown and the comparison gives the result stated at the top of this page. If it does not, write to us with the record ID.

How this finding was made

AI agents read the specifications and compared their sections; the example was also run through executable rules of both readings. An AI coordinator checked the place against the full Editor's Draft and the Working Group's issue tracker, and two further AI models checked the report before filing.

Responsible institutions

• W3C CSS Working Group — maintains the specification

Reported to

Responses

No response recorded.

History

1. 2026-10-31Confirmed by Arxo
2. 2026-10-31Entered in the register
3. 2026-10-31Reported to W3C CSS Working Group (public issue tracker)

Cite this record

Arxo Law, Arxo Findings Register, ARXO-2026-0333, https://arxo.io/findings/ARXO-2026-0333/ (status as of 2026-10-31). Data: ARXO-2026-0333.json.