Re: [csswg-drafts] [css-anchor-position] Various bits of feedback (#12466)

> In Chromium, the block axis seems to be "neither safe nor unsafe".

This is defined in:
https://drafts.csswg.org/css-align-3/#auto-safety-position

And was recently changed in:
https://github.com/w3c/csswg-drafts/commit/3e3151480f6530dcd93af04d2a75a0c656d87be1
https://github.com/w3c/csswg-drafts/issues/12020

(Blink doesn't yet implement this new behaviour but for the example above it doesn't matter).

For `position-area: left` will result in `align-self: anchor-center` `justify-self: end`.

The intent for the `default` overflow is to "shift" within containing-block such that it doesn't overflow. This is what Blink is doing in the block-axis.

WebKit is incorrect in the block-axis AFAICT.

In the inline-axis per the updated specification, WebKit is correct, but IMO this is an undesirable behaviour, as its trivial to overlap the anchor (which is bad IMO).

> In Safari, this is reversed — the inline axis is "neither safe nor unsafe" and the block axis is unsafe.

Its `safe` in the inline-axis. Its applying:

> Otherwise, start-align the [alignment subject](https://drafts.csswg.org/css-align-3/#alignment-subject) within the overflow limit rect (similar to safe).

IMO the default for any non-`anchor-center` should be unsafe for that reason. cc/ @tabatkins 

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Received on Thursday, 10 July 2025 23:35:18 UTC