How to enable Dark Mode for Xcode [duplicate]
On macOS 10.13 High Sierra and earlier
The Dark Mode is only available on macOS 10.14 Mojave.
On macOS 10.14 Mojave and later
1. On Installation: You'll get asked for the appearance as part of the installation of Mojave.
2. After Installation: If you want to change it afterwards go to System Preferences > General and change the Appearance.
2b. On macOS Catalina:You get even a third option to change the appearance automatically based on your Nightshift preferences.
If you use macOS Mojave (10.14.+), you can enable Dark Mode only for Xcode 10 using this command line.
defaults write com.apple.dt.Xcode NSWindowDarkChocolate -bool trueWorkaround:
defaults write com.apple.dt.Xcode _NSSystemAppearanceOverride DarkAppearanceSource (Steve Troughton-Smith's tweet)