Give the possibility to developers to create their own theme

Hello, in the futur can you make possible the theme customisation like BetterDiscord, because I know is against, and when i see that i uninstall the plugin, but in the futur can you make this possible all dev can create their own theme like discord bot but for theme ^^ ? Like vscode with json file or css file or something other I don't know how is it possible to achieve this..

I know you have so much work, but yeah i think planned a feature like would be really well received by the community :) beacause we don't wan't be banned for installing a plugin against your ToS :/ 

Have a good day ;)