Guillaume

Can you please confirm that your intent is to apply the `not all`-ification only in the first case below? 1. `1`: it does not match any branch of the grammar...

Yes, I also assume it. We can already do `CSS.supports('selector(type) and selector(.class)')`, so you could do `CSS.supports('media-query(some-feature: value1) or media-query(some-feature: value2)')` (declaration), `CSS.supports('media-query(some-feature > 1px)')` (range), or `CSS.supports('media-query(some-feature)')` (boolean).

Does option 2 mean that you cannot add a single declaration to the nested `@media` via CSSOM except with `nestedMedia.cssText`? Does option 3 mean adding `.style` to `CSSMediaRule` or does...

> It also means that, for example, deleting everything from .cssRules from an `@media` [`cssRules`](https://drafts.csswg.org/cssom-1/#cssgroupingrule) is read-only.

> **15.2. Serializing sRGB values** > > [...] > > When serializing the value of a property which was set by the author to a **CSS named color**, therefore, for...

Dealing with specified values in *14. Resolving `` Values* confuses me. I would not expect a specified value to resolve. I would expect it to remain (close) to the (tokenized)...

I assume this issue is about serializing all color keywords instead of creating a specific issue or adding noise to #8312. Chrome/FF serialize specified `` to lowercase but: > User...

Changed the title to include the new longhand `transition-behavior`. The issue has been [discussed](https://github.com/w3c/csswg-drafts/pull/9101#discussion_r1272418649) in the related PR. I think dbaron is right that the order does not matter in...

From the comments above, `display: first-valid(foo, bar)` is invalid at parse time. But the current text says: > If none of the arguments represent a valid value for the property,...

In addition to [my comment in #8533](https://github.com/w3c/csswg-drafts/issues/8533#issuecomment-1472051932) (only `` could serialize as specified by the author, without comments and consecutive whitespaces), I think a `var()`-containing value requires to serialize exactly...