To change the desktop color scheme choose + + + → from the main menu. In the Color Scheme list are predefined color schemes. Select the one you like and click on .
You can also define custom color schemes: click on the element you want to change (for example, Active Window to change the active window colors), then on the color bar, choose the color you like and click on to apply it.
To change the desktop background, choose + + + → from the main menu. Select the background picture option in the Background section and background scaling, colors and blending in the Options section.