Please tear apart the UI on my Google Chrome Extension. I'm a back-end kinda guy and don't know how to make this look more appealing.

http://i.imgur.com/r7HkR.png

http://i.imgur.com/SiGxp.png

http://i.imgur.com/ktF1U.png

The top bar's color changes based on the playing state. Paused is yellow. Turns to green when playing and blue when no songs.

I know some of the padding/margins are a bit off, but think on a grander scale. What colors should I be using? I just defaulted to a jQuery UI theme for dev purposes, but it's starting to feel pretty tacky.

The current / total time slide over like the YouTube player when hovering over volume controls.