On Firefox 90, when using Yaru Colors GTK theme and Light Firefox theme, menu/button text is invisible (white on white)

[nyanpasu64]

I am running Linux configured to use Yaru Colors (Yaru-Blue) GTK3 theme. This theme has dark title bars with light text, but light window backgrounds with dark text.

Firefox is configured to use the Light theme, which makes the tab bar's background light gray. And it's configured with "Title Bar" checked, which makes it use the system title bar.

I upgraded to Firefox 90.

Actual results

On both KDE Plasma and GNOME, the menu (whether permanently open or when pressing Alt) contains white-ish text (similar in color to active title bar text) on a light gray background, rendering the menu bar text practically invisible.

(With "Title Bar" unchecked, the menu text is visible, but the minimize and maximize buttons are now white on light gray, and also invisible.)

Switching to Yaru-Blue-Light (most apps have light title bars with dark text) fixes both issues in Firefox, even though with "Title Bar" checked, Firefox strangely still has a dark title bar unlike other apps with light title bars.

Expected results

All text and icons should have consistent contrast.

Also filed at https://bugzilla.mozilla.org/show_bug.cgi?id=1720441.

[nyanpasu64]

Being fixed in Firefox.