Add dark mode styling for the closed banners.
Review Request #13838 — Created May 8, 2024 and submitted — Latest diff uploaded
The discarded/completed banners were too bright in dark mode, having
hard-coded the light mode colors. We now use a dark grey in dark mode,
giving it a distinct feel from the rest of the review request
information, and helping visually indicate that it's closed.
Tested both banner types in light and dark modes.