[csswg-drafts] [css-break-4][css-text-decor-4] Allow breaks to only affect text decorations (#12947)

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

== [css-break-4][css-text-decor-4] Allow breaks to only affect text decorations ==
With the introduction of `text-decoration-trim`, we also defined that it [takes `box-decoration-break` into account](https://drafts.csswg.org/css-text-decor-4/#:~:text=Text%20decoration%20trimming%20is%20subject). So `box-decoration-break` affects whether the text decoration is split or cloned across fragments.

Though `box-decoration-break` also affects other parts of the box, which may be styled differently regarding fragmentation.

Therefore, I suggest a way to differentiate between the layout-related and content-related parts. I see three solutions to this:

1. Extend `box-decoration-break`
Change `box-decoration-break` so that it allows to distinguish to _what_ it applies, e.g. via new keywords that target layout, background, and contents.

2. Make `box-decoration-break` a shorthand
Turn `box-decoration-break` into a shorthand for different longhands for layout, background, and contents. I.e. you'd have `box-decoration-break-layout`, `box-decoration-break-background`, and `box-decoration-break-content`, which take `slice` and `clone`.

3. Introduce a new property
As suggested in https://github.com/w3c/csswg-drafts/issues/8403#issuecomment-3396895682, we might also introduce a completely separate property like `text-decoration-break`.

See also #8535, which refers to allow targetting only the background (and suggests to go either with option 1 or 2).

Option 2 currently seems to make the most sense to me, as it aligns well with what we already have and is backwards compatible.

Sebastian

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12947 using your GitHub account


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Received on Tuesday, 14 October 2025 12:30:38 UTC