@pallacs: Applications should use the OS theme the user has configured whether it's dark, pink, pastel green or whatever.
I don't like dark themes either. Consequently, my OSs are never dark (excet for very specific testing and for very short periods) and my applications shouldn't be, and those that disregard my choice get dumped out. And I would dump it equally if I used a dark theme and an application ignored it and used a clear one.
Whether t's difficult or not to adapt the application doesn't matter: what matters is that applicaitons should follow the theme the user has selected for his OS.