In macOS 10.14 users can choose to adopt a system-wide light or dark appearance and I need to adjust some colours manually depend of the current mode.
To know if the app appearance is Dark, use next code:
+ (BOOL)isDarkMode { NSString *interfaceStyle = [NSUserDefaults.standardUserDefaults valueForKey:@"AppleInterfaceStyle"]; return [interfaceStyle isEqualToString:@"Dark"]; }