+++ This bug was initially created as a clone of Bug #1711258 +++

Note
This issue doens't reproduce when "Display contrast" is set to Normal (default)

Affected versions

• Firefox 89 beta 12
• latest Nightly 90.0a1 2021-05-14

Affected platforms

• macOSX 10.15, macOSX 11.4 beta

Prerequisites

• Set system theme to Light
• Go to System Preferences - Accessibility and select "Increase contrast" option, then move the cursor one level to the right for "Display contrast" item

Steps to reproduce

1. Open Firefox and set the theme to Default or Light
2. Go to about:Support and other about:pages

Expected result

• Every element from about: pages is legible and has enough contrast.

Actual result

The left side of about:support table is not visible

Regression range

• Not a regression, introduced with Proton

Additional notes

• Also reproducible when system theme is Dark and Firefox and Firefox is set to Light theme

Attachment 9222143 [details] is a screenshot of what happens here.

:phorea noted in bug 1711258 that there's no regression range. As far as I can tell there is one for the about:support issue, which was fine in the April 9th nightly, when bug 1700109 (enabling proton by default) landed on April 8th. I think the about:support case regressed with bug 1705133.

Set release status flags based on info from the regressing bug 1705133

https://hg.mozilla.org/mozilla-central/rev/0f1b7efa9337

Can we please uplift to Beta 89?

Comment on attachment 9222290 [details]
Bug 1711580 - use CSS variable with a system colour for table header cell foreground colours to fix high contrast support on macOS, r?mstriemer

Beta/Release Uplift Approval Request

• User impact if declined: Missing text in high contrast mode on macOS
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: See comment 0
• List of other uplifts needed: n/a
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Minimal CSS changes that only affect the (row) header cells in about: page tables.
• String changes made/needed: nope

Comment on attachment 9222290 [details]
Bug 1711580 - use CSS variable with a system colour for table header cell foreground colours to fix high contrast support on macOS, r?mstriemer

Approved for 89 beta 15, thanks.

https://hg.mozilla.org/releases/mozilla-beta/rev/5b9adbb1aff5

Verified fixed on Nightly 90.0a1 2021-05-19 under macOS 10.15.7 and 11.4 Beta.

Verified fixed using Firefox 89 beta 15, OSX 11.4 beta.