How to use a Custom Theme (Gtk3)?

I’ve found a css solution for the checkbox and radio button.
This is how it will look like:

I’m not really happy with the checkbox, but it’s better than the orginal one.

Later today I will upload the final theme in a new topic.

  • New checkbox and radio button
  • Removed the military light green tone background in Load/Save dialogs
  • Removed the ugly dotted focus border which sometimes appears.
  • minor changes

Edit: It’s online now: Final Version