I’m just going to leave this here:
# aqua
defaults write com.hexrays.ida NSRequiresAquaSystemAppearance -bool 1
# dark aqua
defaults write com.hexrays.ida NSRequiresAquaSystemAppearance -bool 0
# default
defaults delete com.hexrays.ida NSRequiresAquaSystemAppearance
ref: How to force Xcode(or any other app) to be on dark theme while macOS Mojave’s setting is on light mode, Choosing a Specific Appearance for Your macOS App