I broke this in bug 1709641.

[Tracking Requested - why for this release]:

FWIW because this broke with bug 1709641 which got uplifted and because it impacts readability exactly for people (on all OSes) who need more contrast, so I think this should be P1 or P2a, and we should get the CSS-only change uplifted to 89.

https://hg.mozilla.org/mozilla-central/rev/646c72ffc272

This issue is Verified as fixed in our latest Nightly build 90.0a1 (2021-05-13), Only the Bug 1709396 and Bug 1709508 remain.

Shilpa, can I request uplift here?

Yes, Gijs. Let's proceed ahead with the Uplift.

Comment on attachment 9221600 [details]
Bug 1710847 - fix high contrast mode interaction with dark mode dialogs, r?mstriemer

Beta/Release Uplift Approval Request

• User impact if declined: Unreadable text when using high contrast mode and Firefox's dark theme
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: See earlier comments
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): 2 CSS changes to put the offending background colour change in a media query that only applies outside of high contrast mode. This won't affect any other UI parts and we can't really make this particular part worse...
• String changes made/needed: Nope

Comment on attachment 9221600 [details]
Bug 1710847 - fix high contrast mode interaction with dark mode dialogs, r?mstriemer

Approved for 89.0b12.

https://hg.mozilla.org/releases/mozilla-beta/rev/81459197dc43

This issue is Verified as fixed in our latest beta 89.0b12 on Mac, Windows and Ubuntu.