Style cleanups
Well, there was a lot more here than expected.
- Use standard styles wherever possible
- When not - update the styles to match them instead
- Make sure the bundle high contrast styles are actually used
This should take care of most of the dark preference support as well. The only missing parts are:
(Nvm that card edges look diferent, it's a libadwaita change that's not in main yet)
Fixes #1524 (closed)
Fixes #1372 (closed)