Burrow UI: window navigation, volume slider

Burrow UI is my personal project to use with apps on Windows. Currently creating foobar2000 UI, but would love to start a company creating solid and simple apps for Windows some day. I think that Windows lacks of task-oriented apps with simple and clean UI.

The additional (grayed out) buttons are for 'Cover Mode' (where app goes full screen and shows big album art) and 'Mini Mode' (where app stays on top of other window and offer minimum UI).