w3c / w3c/csswg-drafts

[css-transitions-2] Explicitly define what is valid/invalid in `@starting-style`

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css-transitions-2
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Description

The spec does not explicitly define what is valid/invalid in its block value. It only says:

Global, name-defining at-rules such as @keyframes, @font-face, and @layer are allowed inside @starting-style [...]

I guess it accepts any rule that is normally allowed at the top-level of a stylesheet, and not otherwise restricted. It does not accept declarations, which means it can be defined with @starting-style { <rule-list> }.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the CSS Transitions Level 2 defining-before-change-style section linked in the issue, and review its wording around @starting-style and global, name-defining at-rules. Done means the specification explicitly states which block contents are valid or invalid, including whether declarations are accepted.

Written by the indexing model from the issue text.

Assessment

Tech stack
css
Domain
documentation
Issue type
Documentation
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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