Btw, the resolution should be consistent with VTT STYLE blocks since it has a similar role and the same cascade precedence as the style attribute.

This gives a stronger reason to choose option 1, since banning revert-layer from the VTT STYLE block makes things even more complicated.

I'm happy with that approach. Agenda+ for discussion/resolution.

Elika and I agree that since style attributes are now in their own origin, they (implicitly) sit in their own unlayered layer, unrelated to any author-level layers. (And with no way to declare any additional layers.) So yeah, it would just roll back to the previous origin, the author layer, which is the suggested Option 1 behavior.

The CSS Working Group just discussed [css-cascade] revert-layer keyword in style attribute, and agreed to the following:

• RESOLVED: it would revert the style attribute and nothing else

I think technically all that's needed here is a note, but we should have a note.

I don't think we technically made element-attached styles into an origin, though maybe the implications are similar (or we should move them into an origin). Currently they have their own stage of the cascade: https://drafts.csswg.org/css-cascade-5/#style-attr

Maybe a note is still enough? Something similar to the note regarding origins?

@xiaochengh let us know if the edits in a64a842 satisfy the question here.

Not a strong opinion, but I would like to see if an alternative idea may work.

a64a842 says if we have style="foo: revert-layer !important", it will make all important author styles ignored, and land on the normal level of the top author layer. While this follows from the spec text "as if no rules were specified in the current cascade layer—or between its normal and important levels in the cascade", it's a bit unintuitive to me as now the author layers are half-ignored. In contrast, revert-layer in regular style sheets always makes any layer either fully ignored or fully retained; similarly, revert always makes any origin fully ignored or fully retained. It will also make the implementation in Blink a bit more tricky (though still doable).

My original mental model is that revert-layer makes everything in the current layer and all layer above ignored, so style="foo: revert-layer !important" will revert to the important level of the top author layer. I'm not sure how to specify that nicely, though. The closest thing I've come up with is by revising the definition of revert-layer into:

... so that the specified value is calculated as if no rules were specified in the current cascade layer and any succeeding layer in the layer ordering for this property on this element.

The only problem is that the style attribute is not in the layer ordering, and it cannot be simply treated as a layer or origin due to !important...

Anyway, this is not an opposition. I have some concerns with a64a842 and I'll be happier if my original mental model works, but I can still accept a64a842 as the final spec.

@xiaochengh to diagram, the current spec works like:

* - where revert-layer is defined
x - additional layers reverted
@ - the top layer to be applied

user agent     !important
style          !important       * 
author layer A !important *     x 
author layer B !important x *   x 
author layer C !important x x * x 
animations                x x x x 
style          normal     x x x x 
author layer C normal     x x x @ 
author layer B normal     x x @   
author layer A normal     x @     
user agent     normal     @

And you're proposing a much more limited scope, where only the current layer is reverted, separately for normal and important versions of a layer? Something like:

user agent     !important
style          !important       * 
author layer A !important *     @ 
author layer B !important @ *     
author layer C !important   @ *   
animations                    @   
style          normal         
author layer C normal
author layer B normal
author layer A normal
user agent     normal

To some extent, both of these will be new and possibly unexpected for authors, who have generally not thought about importance-reversal before now. Authors are likely to try reverting styles in a normal layer by using !important as an override. Although it has some additional implications, the current proposal achieves that goal - using the important layer to revert the normal layer.

I don't think it makes sense to revert the normal and important versions of a layer without touching the layers in-between? If authors want to override a normal rule with revert-layer, avoiding those implications, they can do that using specificity instead.

I'd be interested in @jensimmons perspective on this as well.

And you're proposing a much more limited scope, where only the current layer is reverted, separately for normal and important versions of a layer?

No. My mental model works like:

user agent     !important
style          !important       * 
author layer A !important *     @ 
author layer B !important x *    
author layer C !important x x *  
animations                x x x x 
style          normal     x x x x 
author layer C normal     x x x  
author layer B normal     x x @   
author layer A normal     x @     
user agent     normal     @

That's what I meant by "revert-layer makes everything in the current layer and all layers above ignored". There's no behavioral difference to the current spec text unless there's a revert-layer in style.

In this example, we ignore style and animations, but not anything in author layers A/B/C because they are below style (assuming style is a layer above A/B/C, though this does seem a bit ill-defined).

@xiaochengh aha, I agree that would likely make sense from an author perspective - and is a more direct interpretation of the resolution. Thoughts, @fantasai?

Yes. Thinking about this more, I'm not sure what's more intuitive as a model, but certainly if you have written some styles into a layer and are expecting your !important rules to override your normal rules, but we remove only the !important rules, things are likely to break. So I think we have to go with @xiaochengh's model.

The CSS Working Group just discussed revert-layer keyword in style attr, and agreed to the following:

• RESOLVED: Accept suggested behavior, where `revert-layer !important` in style attr only reverts the style-attr origins and the animations origin, ignoring other author origins

The spec already reflected this resolution, so closing. ^_^