Seems a little, uh, extremely painful to look at. Bright colors don't go with Steam because you're going to be looking at it a lot, and if you stare at a hot pink box for about 40 minutes you're going to get massive amounts of headaches and eyestrain.
Also, it's very very VEEEHEHEHERY niche. If I watch some guy on YouTube, I'm not gonna friggin' modify my programs to make it match is YouTube theme. That'd just be kinda weird.