Re: [csswg-drafts] Proposal: CSS Text Transitions & Animations (#13689)

Definitely recognize and agree that this would be a big feature. At this point I'm mostly looking to stress-test the idea and understand whether it's feasible and interesting to pursue. Good questions @astearns; I'll offer some initial thoughts:

> 1. How would we represent intermediate steps here?

To clarify, are you asking about computed value? If so, I think the most consistent and predictable thing would be that computed value would follow the value of the first animated unit, and the remainder of the text animation would be (from a values standpoint) a presentational effect. That way, the values surfaced to inheritance and on the OM look the same regardless of text length, and they are consistent with what would be exposed if the effect were running without a text transition. I would also be open to having an API that surfaces intermediate values on subsequent text units, but I think that's something other than the element's computed value.
 
> 2. How does the parent animation interact with children that have set the animating property to a different value?

For a lot of properties, I think the answer is probably similar to what happens with whole-element transitions and animations. If the child element would inherit a value from the parent, it participates in the effect.

`opacity` and similar are more interesting cases, because they're not inherited but implicitly affect the entire subtree. These I think would need to be special cased such that words in descendant elements *do* participate in the effect.
 
> 3. How would this interact with text shaping, or other changes in layout for adjacent characters that momentarily have separate values applied?

I'll admit text shaping is not an area I have a ton of expertise in. But I think that breaking text into units for these effects happens downstream of text shaping and line breaking, regardless of the unit the author has selected. For example, I would not break ligatures in English and similar languages to animate each letter individually.

> 4. Have you consulted with the SplitText folks about solving this problem in-browser?

I haven't yet; this proposal is still pretty warm out of the oven.

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Received on Monday, 23 March 2026 05:05:42 UTC