Reproduction steps

1. Install the matrix-auth plugin.
2. Activate the theme.
3. Go to "Manage Jenkins" > "Security" and scroll down to the "Authorization" section, selecting "Matrix-based Security"

Expected Results

A table is shown in line with the theme and with all text readable.

Actual Results

A table is shown where the heading for the first column as well as the group headings for the rest of the columns use a non-theme pale background, but with the theme's foreground color for the text, making it unreadable (because for a dark theme, that text will be pale).

Anything else?

Initially reported as JENKINS-76031, but Daniel Beck identified this as a regression in the theme, so reporting it here now.

Also reported for the Solarized Dark theme at Matrix Auth table headings unreadable - Issue #92 - jenkinsci/solarized-theme-plugin (and it also applies to the Dark, Chocolate and Catppuccin Mocha themes, from the same maintainer).