[csswg-drafts] [css-break] box-decoration-break:clone on the root (#13706)

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

== [css-break] box-decoration-break:clone on the root ==
`box-declaration-break: clone` cause the background of an element to be repeated in each fragment (rather than sliced) if the element is fragmented.

However, the background set on the `:root` element is not painted on the root element, but instead propagated to the canvas ([see css-backgrounds-4](https://drafts.csswg.org/css-backgrounds-4/#root-background)].

I think this means it's not clear what happens in a paginated content. The root element is fragmented over multiple pages, but we're not painting its background. Is the canvas fragmented? Does `box-declaration-break` propagate to it?

In other words, if I have to top-to-bottom blue-to-orange gradient as the background of my `:root`, to I get a top-to-bottom blue-to-orange gradient on every page, or a single one that goes from blue at the top of the first page, to orange at the bottom of the last page?

My intuition would be that with `box-declaration-break: clone` on the `:root`, you get a gradient per page, and otherwise, you have a gradient running through the whole set of pages, but I cannot find spec language to decide either way, and I do not think we have interop. Firefox has a clone-like behavior which does not seem to respond to `box-declaration-break`, while Chrome and Safari have a slice-like behavior which also does not seem to respond to `box-declaration-break`.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13706 using your GitHub account


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Received on Tuesday, 24 March 2026 08:53:49 UTC