Please fix the dark theme

First of all , thank you very much for eM Client !
As a macOS refugee it seams to be the closest app compared to Apple Mail.

I would even buy the software (no subscription please) just to get teh following fixed:

Anytime I open eM Cleint I first shows white and then the Dark themes kicks in.
That results anytime in a bright white disturbing flash which makes eM Client always look broken.
It woudl look much better if teh window would be dark from the beginning.

Please fix this <3