Can anyone on the @bsky.app mobile team (@samuel.bsky.team @hailey.at?) able to talk about the choice of building an ad-hoc styling/theming system instead of using something like Nativewind or Restyle? 
Nativewind has some pretty significant performance issues from my understanding (not the worst of the batch but not the best). I think Restyle is pretty good though!
I'm not exactly full on the context of why we did that, it was before I joined. Maybe @esb.lol has some info.