I'm someone who prefers to have Soulver (and other apps) match the system's current light/dark theme for consistency. Unfortunately, this means that when I attempt to customize my style settings, I can't really do that effectively, because those style settings apply to both dark and light themes. For example, if I change my "other text" color to a particular shade of dark gray to match the light theme, that same dark gray will be almost completely unreadable when my system switches to dark theme.
Having a way to assign colors specifically for the light theme and then pick different ones for the dark theme would be really fantastic. Right now, I actually can't customize the colors as much as I'd want to, because I have to make sure the colors are readable in both themes.