Make UI more compatible with dark mode
Some UI elements don't look very good when using dark mode in MacOS (not too surprising, see https://www.reddit.com/r/UXDesign/comments/ydt5fc/do_you_think_this_delete_button_design_is_okay_in/). In light of this, effort should be taken to look through the whole program and fix the parts of the UI that looks bad in dark mode.