Re: [csswg-drafts] [scroll-animations-1] Allow `<length-percentage>` in `<keyframe-selector>` when combined with `<timeline-range-name>` (#10000)

After reading #10879, maybe we should allow `<length-percentage>` inside `<keyframe-selector>` in general, to open up the `scroll-timeline` case as well?

```css
@keyframes f {
  0% { translate: 0% 0%; } /* ✅ Allowed */
  150px { translate: 0% -100%; } /* ❌ Not allowed */
}

el {
  animation-name: f;
  animation-timeline: scroll();
}
```

_(These are the keyframes for something like [this shrinking header](https://scroll-driven-animations.style/demos/shrinking-header-shadow/css/) that animates using the `animation-range` `0px 150px`)_

If we don’t want this extra addition, the [current proposal](https://github.com/w3c/csswg-drafts/issues/10000#:~:text=name%3E%20%3Clength%2Dpercentage%3E%3F%20%5D%23-,Proposed%20Solution,-Allow%20%3Clength%2Dpercentage) can already work if we enable `scroll` to target the full range of the `ScrollTimeline` (see request [here](https://github.com/w3c/csswg-drafts/issues/9367#issuecomment-1905788011)):

```css
@keyframes f {
  scroll 0% { translate: 0% 0%; } /* ✅ Allowed */
  scroll 150px { translate: 0% -100%; } /* ❌ Not allowed */
}

el {
  animation-name: f;
  animation-timeline: scroll();
}
```


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Received on Friday, 20 September 2024 08:30:17 UTC