With OSX 10.10 beta 3, Apple released their dark tint option. Unfortunately, it also means that pretty much all status bar icons (with the exception of Apple\'s and Path Fin
But just in case you do want to monitor the status changes you can. I also know there is a better way to determine lite/dark mode than what's been said above, but I can remember it right now.
// Monitor menu/dock theme changes...
[[NSDistributedNotificationCenter defaultCenter] addObserver: self selector: @selector(themeChange:) name:@"AppleInterfaceThemeChangedNotification" object: NULL];
//
-(void) themeChange :(NSNotification *) notification
{
NSLog (@"%@", notification);
}