Feature Request: Dark/Night UI

[phuyuk]

Since many of the presets are aimed at relaxation, sleep induction, meditation, etc - activities that are suited to a darkened environment - an optional subdued or black UI would be very helpful. This would help to avoid a significant white-light stimulus (from a 12" tablet, in my case) while experimenting with various 'sleep' presets, for example. The benefit is practical, not aesthetic.