You can customize the color layout for the web client from the Global Settings Themes page or the Domain Themes page. On the Themes page you can select colors from a pallet table for the following user interface base colors:
Foreground color is the text color. The default text color is black. This is not often changed.
Background color is the primary background color displayed in the client. This color is the background for the page. Variants of the color are used for buttons, background color of the Content and Navigation panes, tabs, and selection highlight. In the following image, the background color displays with the login section, the variant of the background color displays in the background page.
Secondary color is the color used for the toolbar.
Selection color is the color displayed for a selected item such as a message or an item selected in the Navigation pane.
Because changing the base colors from the administration console changes the colors for all themes, you may want to limit the themes that are available to your users to one theme.