Hello everyone I know that there are several threads about this but they are all mixed with other stuff about features, etc. At WWDC (2014) Apple introduced a "Dark Mode" for Yosemite. I think this is a good step but they have to move it all across the system. Mail, Messages, etc this could be all done quite easily. I like the new UI of OSX and iOS both in dark areas and at night the screen is just way to bright therefor there should be Dark Theme. For certain apps this is already done I think about iBooks. So hopefully this will be one of the few new features that they will introduce at WWDC '15.