In case you're talking about REI's dark mode (which I will assume you are), it is now supported in our development builds. It might take a while however before we release this, as it is not a critical bugfix and we usually don't do releases for such small features
Cheers

Yes, thank you very much.

REI's dark mode

plus the craft interface when we right click in the world Alloy device (and probably grouping icons for the owolib creative tab).