Re: [csswg-drafts] Defining `@custom-media` inside conditional at-rules (#12536)

But can't you do that with something like this at the top level?

```css
@custom-media --foo ((screen) and (...)) or ((print) and ...);
```

I guess not because `screen` and `print` are media-types, so you'd need two separate queries (`--foo-screen` and `--foo-print` or so?). That seems something that if needed we could easily lift if needed.

But yeah it's a good point that conditional stylesheets make this harder... To be fair, what I don't want is having to overcomplicate how we process stylesheets so that we need multiple passes, since that's already fairly hot code for pageload.

I wonder if an alternative is saying that `@custom-media`s don't apply "backwards", e.g.:

```css
@custom-media --foo ...;
@media (--foo) {
  /* This uses the `--foo` from above, not the one below */
}
@media (--bar) {
  /* This never applies, `--bar` is not defined */
}
@custom-media --foo ...;
@media (--foo) {
  /* This uses the second `--foo` media */
}
@custom-media --bar ...;
@media (--bar) {
  /* This one works */
}
```

-- 
GitHub Notification of comment by emilio
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12536#issuecomment-3132011705 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Tuesday, 29 July 2025 11:23:17 UTC