Probably the easiest thing to do is install a new desktop theme with a different color mix. How to do that really depends on which desktop you are using. If you are farmiliar with your desktop theme files and where they are located, you may be able to open them and edit the color entry. You can change that dark grey color to red or gold e.g. You have to know where to look. We don't know what desktop.
i5 3570k, ASRock z77 Extreme 4, 8 Gb Ripjaws 1600, Antec 430w psu, HVR 1600 tv tuner, custom case- marble top, oak face. Carver & DCM Time Window sound system. Mint 14 KDE.