CSS Cascade 5: what does revert-rule roll back in a style attribute?

§7.3.6 rolls revert-rule back “as if the current style rule had not been present”. §6.1 separates declarations in a style attribute from style rules, and §7.3.6 has a sentence for the animation origin but none for the style attribute. The same question for revert-layer was settled in issue 6743 with a dedicated sentence in §7.3.5. Browsers already agree on normal declarations: the web-platform-tests case for a style attribute passes in Chrome, Edge, Firefox and Safari with the 5px result (stable runs of 31 October 2026); no test covers !important.

Consequence

div { border-radius: 5px } and <div style="border-radius: 2px; border-radius: revert-rule">: if the whole attribute counts as the current rule the result is 5px; if only the declaration with revert-rule is removed it is 2px.

Proposed correction

Extend the §7.3.6 sentence “behaves like revert-layer in the animation origin” to element-attached styles, which matches the browser tests and brings in the §7.3.5 rule for important declarations.

Issued by

World Wide Web Consortium (W3C) — CSS Working Group

Act

CSS Cascading and Inheritance Level 5 (Editor's Draft, 13 April 2026)

Place

§7.3.6, read with §6.1

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.

If the cascaded value of a property is the revert-rule keyword, the cascaded value is rolled back such that the specified value is calculated as if the current style rule had not been present at all.

declarations that are attached directly to an element (such as the contents of a style attribute) rather than indirectly mapped by means of a style rule selector

The revert-rule keyword behaves like revert-layer in the animation origin.

How to check it without Arxo's tools

1. Open CSS Cascading and Inheritance Level 5, Editor's Draft of 13 April 2026 (W3C CSS Working Group) and find §7.3.6 Rolling Back Rules: the revert-rule keyword; §6.1 Cascade Sorting Order, Element-Attached Styles. Compare the text with the quotation above. A copy is kept in this register: 2c51fc71d5bfec21-ed-css-cascade-5.html (SHA-256 2c51fc71d5bfec21aee9acf5004344fc0b5197db31fc48a1ae5373f3fbc4670f, 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-2026-0336, https://arxo.io/findings/ARXO-2026-0336/ (status as of 2026-10-31). Data: ARXO-2026-0336.json.