Get it here and visit the app to customize
I've been distracted by a full-time job, and other side projects and probably won't have time to fix the long list of bugs introduced by Proton UI for a while. If you would like to help out in any way, please ping me or open a pull request.
Some of the code, namely urlbar and popups CSS are slighltly edited versions of the ones from Material Fox.
All the icons are from Remix Icons