Dark User Interface

Recently I have been seeing much talk of built in features - or lack thereof - for SketchUp and Layout.
One feature I think would be great and would ease my day is a dark UI. Its a common feature elsewhere.

My eyes would thank me. I find dark themes across programs helps to reduce eye fatigue, especially if I need to be at the computer all day or week.

Is it that the current UI colour set is matter of branding?