[css-cascade-5] revert-layer in element-attached styles

[bramus]

As per https://drafts.csswg.org/css-cascade-5/#revert-layer, revert-layer in important element-attached styles should revert back to the author origin:

For revert-layer in important element-attached styles, however, it only reverts the element-attached styles and the intervening animation origin, and not any of the intervening author-origin important rules.

https://wpt.live/css/css-cascade/revert-layer-009.html however seems to imply this is also the case for regular element-attached styles, with all vendors agreeing on this behavior.

Suggestion to update the spec to the following, dropping the word “important”:

For revert-layer in element-attached styles, however, it only reverts the element-attached styles and the intervening animation origin, and not any of the intervening author-origin important rules.

[bramus]

/ping spec editors @fantasai @mirisuzanne @tabatkins

[mirisuzanne]

@bramus Both revert to styles within the author origin. That note is specifically about how to deal with intervening important rules. In the example you linked -- and always when the inline styles are not marked as important -- there are no intervening important rules:

- !important UA origin
- !important User origin
- !important Element attached (reverting from here…) ⏪
- !important Lowest Layer (…maintains these layers)
- !important Highest Layer (…)
- !important No Layer (…)
- Animation origin (…but would revert this one) ❌
- Element attached (…and this one. But the linked WP test starts here…) ❌
- No Layer (…and ends up here, which is also correct)
- Highest Layer
- Lowest Layer
- Presentation hints
- User origin
- UA origin

[bramus]

Very helpful comment. Thanks for clarifying.