w3c / w3c/csswg-drafts

[css-conditional-5][css-nesting-1] Feature detection for nesting

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css-conditional-5 css-nesting-1
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Description

We need to provide a smooth way to transition to nesting, so authors can detect whether nesting is supported by the user agent. So they can provide fallback solutions for UAs that don't support it.

There where already some prior discussions related to this topic, though no explicit issue or resolution regarding this, as far as I can tell.

The major discussion related to this is #8349, but its focus is rather on error recovery than feature detection. Another slightly related one is #2463, though it rather features detection of at-rules and their descriptors.

So I opened this issue to explicitly discuss how nesting support can be made detectable. I believe this is a must for any implementation for shipping nesting capabilities to reach a high level of adoption and avoid page breakages.

Sebastian

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the issue text and the related discussions in #8349 and #2463. The work needs a resolved specification approach for detecting CSS nesting support, with a clear definition of what authors can use and what constitutes completion.

Written by the indexing model from the issue text.

Assessment

Tech stack
css
Domain
frontend, web-dev
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Active
Clarity
Needs clarification
Newbie friendliness
25/100

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