- From: Emilio Cobos Álvarez via GitHub <sysbot+gh@w3.org>
- Date: Wed, 27 Oct 2021 23:33:43 +0000
- To: public-css-archive@w3.org
emilio has just created a new issue for https://github.com/w3c/csswg-drafts: == [css-color] [css-color-adjust] Consider reversing the resolution of #3847 == In https://github.com/w3c/csswg-drafts/issues/3847 it was resolved that system colors would compute to themselves. The argument for that seems sensible (which is that color-scheme would be automatically honored for them while inheriting). However I'm not so sure that's great behavior (plus there are still open issues from that change like https://github.com/w3c/csswg-drafts/issues/5780). In particular, in order to guarantee contrast, you need to use system color _pairs_ (the foreground and the background), such as: ```html div { background-color: Canvas; color: CanvasText; } ``` If color-scheme changes, but the author _doesn't_ specify a background, making system colors compute to themselves at computed-value time breaks contrast ([rendered](http://crisal.io/tmp/color-scheme-change-no-background.html)): ```html <!doctype html> <style> :root { color-scheme: dark } span { color-scheme: light } </style> I'm dark, and <span>I'm light</span> ``` The `span` should be dark text over dark background per spec, since it inherits the initial color which is `canvastext`, which is undesirable. That's clearly not how browsers are working today, which confuses me because I thought Chrome implemented this change. I'd expect this test-case to render per spec the same as the following ([rendered](http://crisal.io/tmp/color-scheme-change-no-background-explicit-color.html)): ```html <!doctype html> <style> :root { color-scheme: dark } span { color-scheme: light; color: CanvasText } </style> I'm dark, and <span>I'm light</span> ``` (which is clearly undesirable, and not what's going on). Can you explain what's going on here @futhark / @andruud / @kbabbitt / @tabatkins? cc @smfr Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6773 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Wednesday, 27 October 2021 23:33:45 UTC