Re: [csswg-drafts] [css-page] Expose unprintable areas via CSS (#11395)

> I have one suggestion on this part of the suggested spec-text:
> 
> > page-margin-safety only affects margins that are adjacent to a page's edges. In other words, when page-margin-safety is specified in a margin context, it will only have an effect at one or two sides.
> 
> **Suggestion:** For the purpose of making this easier to reason about and to spec, it's probably simplest to handle this by just defining the `<safe-printable-inset>` as being `0` on **all sides of a page-margin-box that are adjacent to the `page box`** (i.e. all of the sides that are facing inward toward the document).

Sounds good, except that it cannot be "page box". That's the entire thing. Either "page area" or "page border box" (if that one is sufficiently defined in the spec), https://drafts.csswg.org/css-page-3/#page-model 

> Also: I think we **need to be very careful** to define how `@page { page-margin-safety: [clamp|add] }` impacts the size & placement of the margin boxes -- specifically, we need to define what it means for the algorithm in https://drafts.csswg.org/css-page-3/#fixed-sizing (section 5.3.3). We can perhaps leave the details to spec-editors [...]

Good point. Yes, safe margins need to be taken into account before layout. Auto margins need to be taken into account both before (to shrink any non-fixed box size) and after layout (position the box within the safe area).

Maybe this is a start: https://github.com/w3c/csswg-drafts/pull/13190/files

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Received on Monday, 8 December 2025 14:27:51 UTC