Hey guys, thought I'd make this guide for some of you who are interested in having a custom premade theme, or if you're good at css you can make one yourself.
First off go to this link https://github.com/rauenzi/BetterDiscordApp/releases
Download either the mac or windows version of the file and install it like you normally would do with any other application.
Then go to your Discord settings and on the bottom you will see a new section appear. Click on themes.
Now you can import whatever theme you have which you can get from Google.
Just activate and you're done!
Here's a theme and custom bg I used for myself:
Preview:
https://betterdiscord.net/ghdl/?id=2917
In Custom CSS: