[Feature] Custom CSS injection

[philipjholm]

I was asked to create a feature request for this so here it is :)

It would be nice if a user could have the possibility to write custom CSS in the settings that would then be injected after the apps default styling. This would mean that more advanced users could personalize the app more and could even lead to people making themes for it in the future.

[gantoine]

Theming is a cool idea, but low priority at the moment, as we're still trying to nail core functionality. If there's a specific change to the UI you think would benefit most users let us know!