Review contrast of colors used in 'night' mode

The blue icons on the black background are hard to read on smaller devices. We need to review contrast in relation to accessibility.

No file, test, or entry point is named in the issue. Start by locating the night-mode color definitions and the blue icon usage, then review them on smaller devices against accessibility contrast guidance. Done means the icons are readable against the black background and the contrast review is addressed.

Written by the indexing model from the issue text.