`pane-header` doesn't respond to dark theme

[NotMyFault]

Jenkins and plugins versions report

ci.jenkins.io, plugin version 574.va_19f05d54df5

What Operating System are you using (both controller, and any agents involved in the problem)?

N/A

Reproduction steps

Take a look at a table using pane-header, e.g. used by the matrix auth plugin in yourJenkins/manage/configureSecurity/ and notice it's not colored.

Expected Results

The panes are colored as intended.

Actual Results

Anything else?

No response

Are you interested in contributing a fix?

No response