A few days ago I did a backup using deja dup, which took up an unanticipated 18GB on my disk. Then a torrent I was running filled up the rest of the space at the same time. When the screen timed out I couldn't log back in (assuming it's related to the disk space) so I rebooted. Everything started normally but I had weird theming and icon issues (see attachments below).
Dolphin missing icons.
Firefox with title bar disabled and no window controls showing up.
Missing icons in the menu
Missing icons from the settings.
Software centre looks completely messed up.
Geary looking like the software centre.
Libreoffice looking the same.
I can choose Breeze Dark and almost everything looks normal (Software Center, Geary and Librefoffice are still weird though) but as soon as I go back to SolusDark theming then everything reverts to the weirdness above.
Any thoughts on how I can reset back to default theme/icons?