Allow custom themes

It would nice if you are able to submit a custom theme without other ways that break TOS like a section in discord that shows everybody custom theme since it on discord it would be easy to moderate what to accept and whats dangerous. As it would have a section on what kind of theme it is. Because it would sometimes be boring looking at the same thing over and over again. I don't know css for the custom themes but could either check them before putting them out.