I finally finished the TH Theme Toggler userstyle so that users can quickly toggle between the different TH themes without having to manually go change it in Settings each time so that they can check if their custom coloured HTML is readable on all themes 😭 It's unnecessarily long, and I'm sure I could condense it, but maybe I'll do that some other time. Not any time soon though.
I was gonna include an option where users can choose/ customize their own theme colours, but because of how long the code is already, I think I might just make a separate userstyle for that 🥲