[csswg-drafts] [css-view-transitions-1] Scope of the "user-agent origin" stylesheet (#8069)

jakearchibald has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-view-transitions-1] Scope of the "user-agent origin" stylesheet ==
In view transitions, we [dynamically update styles in the user-agent origin](https://drafts.csswg.org/css-view-transitions-1/#animate-a-view-transition-algorithm). (I'm not happy with the prose of that section, so don't worry too much about that)

In Chrome, there's an instance of the user-agent origin stylesheet per document, so the modifications we make only impact the current document. However, the [cascade spec](https://drafts.csswg.org/css-cascade-5/#cascading-origins) suggest there may only be one user-agent origin stylesheet , therefore the modifications we make in the view transitions spec would impact other documents, which is bad.

My gut instinct is that we should spec a new cascading origin for view transitions, and specify that there's one instance per document, so modifications will only apply to that document. The [cascade spec](https://drafts.csswg.org/css-cascade-5/#cascading-origins) already mentions an "animation origin" and a "transition origin", which feel similar, although I don't see any usage of those in the linked specs.

@mirisuzanne: I think you might know the right way to spec this.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/8069 using your GitHub account


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Received on Monday, 14 November 2022 15:13:57 UTC