Re: [csswg-drafts] [css-position][css-anchor-position] Splitting Scrollable Containing Blocks (#12607)

Precise proposal: 

```
position: <position-type> || <position-attachment> || <position-container>

<position-type> = static | relative | sticky | absolute | fixed
<position-attachment> = auto | local | scroll | viewport
<position-container> = nearest | farthest
```

* Temporarily removing the `<dashed-ident>` from "container", as that's a separate issue. We can add it back later.
* The `fixed` value causes an unspecified attachment/container to default to `farthest` and `viewport`. Otherwise it's identical to `absolute`.
* Other than the above, omitted values default to `absolute`, `nearest`, and `auto`.
* The property's initial value is still `static`, of course.

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Another possible slight variant:

```
position: static | relative | sticky | fixed | [ absolute || <position-attachment> || <position-container> ]
(<position-container> and <position-attachment> as defined above)
```

* This disallow silly combinations of static/etc with attachment/container values, and leaves open the possibility of other type-specific controls (I think `sticky` has a chance to grow some more, for example)
* `fixed` also loses configurability, which is probably good. `fixed viewport` is redundant; `fixed local` is contradictory. It just "behaves as " `absolute nearest viewport`.

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Received on Thursday, 21 August 2025 11:33:17 UTC