[csswg-drafts] [css-images-4] Can we allow `image-set()` as an argument to `light-dark()`? (#13709)

bramus has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-images-4] Can we allow `image-set()` as an argument to `light-dark()`? ==
One of the responses I got to `light-dark()` now also supporting two `<image>`s as arguments is this:

> Combining and extending image-set with light-dark would be neat!

Basically, the author wants to do the following:

```css
html {
 color-scheme: light dark;
 background-image: light-dark(
  image-set(
   "image1-light.jpg" 1x,
   "image2-light.jpg" 2x
  ),
  image-set(
   "image1-dark.jpg" 1x,
   "image2-dark.jpg" 2x
  ),
 );
}
```

The problem here is that `image-set()` is not allowed as an `<image>` argument, as [per spec](https://drafts.csswg.org/css-images-4/#image-set-notation):

> The `image-set()` function can not be nested inside of itself, either directly or indirectly (as an argument to another `<image>` type).

I don’t know the history of this limitation _(and the spec doesn’t seem to mention anything about it)_, but the request from the author seems like a reasonable thing to ask for.

Can we relax things here? Or is this a no-go?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13709 using your GitHub account


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Received on Tuesday, 24 March 2026 12:35:25 UTC