[csswg-drafts] [css-pseudo] Define ::backdrop (#7845)

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

== [css-pseudo] Define ::backdrop ==
Right now `::backdrop` is defined in https://fullscreen.spec.whatwg.org/#::backdrop-pseudo-element

> Each element in a [top layer](https://fullscreen.spec.whatwg.org/#top-layer) has a ::backdrop pseudo-element. This pseudo-element is a box rendered immediately below the element (and above the element before the element in the set, if any), within the same [top layer](https://fullscreen.spec.whatwg.org/#top-layer).
> It does not inherit from any element and is not inherited from. No restrictions are made on what properties apply to this pseudo-element either. 

Well, there are several details that are not clear to me:
 - Is it a tree-abiding pseudo-element?
 - If it's a tree-abiding pseudo-element, where is it originated? Before `::marker`, between `::marker` and `::before`, between `::before` and 1st child, between last child and `::after`, after `::after`?
 - It accepts random properties, e.g. `display: list-item`. But then:
    - Does it really become a list item?
    - If it becomes a list item, does it increment the implicit `list-item` counter as usual? If so, it's position in the tree matters.
    - Do counter properties even work in `::backdrop`? The properties are defined as applying to "all elements (includes ::before and ::after pseudo-elements)", but the `::backdrop` definition says "no restrictions".
    - Does it originate a `::marker` pseudo-element?
    - Should `::backdrop::marker` be a valid selector?

I think css-pseudo should define `::backdrop` and clarify these details.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7845 using your GitHub account


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Received on Thursday, 6 October 2022 23:10:28 UTC