[csswg-drafts] [css-fonts-3] Composite font faces with non-identical descriptors (#13626)

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

== [css-fonts-3] Composite font faces with non-identical descriptors ==
  Regarding the font matching algorithm (ยง5.2, step 4), the spec says:

>   If a font family match occurs, the user agent assembles the set of font faces in that family and then narrows the set to a single face using other font properties in the order given below. A group of faces defined via
>   @font-face rules with identical font descriptor values but differing 'unicode-range' values are considered to be a single composite face for this step:

  However, I think there are cases where two faces don't have identical descriptors (except for unicode-range) but should still compose a single face. For example, if the request specifies font-weight: 400 and we have:

  - A: `font-weight: 400, unicode-range: U+0-FF`
  - B:  `font-weight: 300 500, unicode-range: U+100-1FF`

  Both faces include the requested weight value, but their descriptors aren't identical. Should they form a composite face?

  This came up while working on a WebKit change to properly isolate non-matching faces: https://github.com/WebKit/WebKit/pull/60035

  Maybe the spec could clarify how composite faces work when a descriptor uses a range value.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13626 using your GitHub account


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Received on Tuesday, 10 March 2026 16:53:03 UTC