We'll probably improve that for dark themes in the future. (The border comes from the Windows theme, but if you have Opus configured to look nothing like the rest of Windows, it doesn't look great.)
I've been messing around with this theme but My Computer is now exactly showing up correctly (My Computer is set to non-native view). Basically the text is black with the dark background. Any ideas of what exactly is governing the colors here? Because it's a bit of a mess and I can't figure it out.
Turn Preferences / Folders / Virtual Folders / Native display of 'Computer' back on, so Opus handles the folder itself.
If using dark background colors, turning off Preferences / Display / Options / Enable background images in virtual folders is also advised, since views provided by the Windows shell will still use black text.