Re: [csswg-drafts] [css-fonts][css-values][css-viewport] UAs inconsistent in how OS font settings affect the default font-size `medium` (#10674)

> I discussed this issue with an author today. The feedback was that she and her team work in `px`, want to continue to work in `px` and, importantly, want to obey the user's system font preferences without spending years tediously converting their existing sites to use a new unit.

Authors will always be free to do that, but it's worth pointing out that that goes against [WCAG 2.2's resize text success criterion.](https://www.w3.org/TR/WCAG22/#resize-text)

> If we ship `uem` as described, I believe it is not possible in CSS to derive a `%` value that can be passed to `text-size-adjust`. We'd be leaving these authors, and subsequently their users, out in the cold.

Out of curiosity, how would you derive a percentage from an `env(system-font-scale)` for the system font size. Presumably, it would still compute to an absolute length? Or is this a different `env` property to what we've already discussed that provides the scaling percentage?

Plus, my understanding of text-size-adjust is that the UA will only do the adjustment in certain circumstances, like when there's no `<meta viewport>` tag. I didn't see it working in Chrome for Android on this CodePen. I don't know if I'm missing something? https://codepen.io/joshtumath/pen/mybQmqW

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Received on Friday, 24 January 2025 17:25:05 UTC