After selecting the "Advanced" tab in the Settings page, select the "Look & Feel" tab.

Click on the "Select a Color" link next to the corresponding navigation bar. By using the Colour Selection Tool that appears, select the colour you wish to assign to the navigation bar by dragging your cursor to the desired colour.

Don't forget to click the "update" button at the bottom of the page to confirm your changes. You may reset you color scheme by clicking on the "Reset" button.