Themes work by building on activeCollab's default styling with CSS files that are added once the basic styling elements (page layout, form widgets and other basic page elements) have been loaded. These basic elements serve to make activeCollab fully usable, but with a minimum number of graphic elements on the page.

To see how activeCollab looks with only basic files included, select the Sandbox theme on your profile page.

When changes to basic styling are required, activeCollab uses theme files to override these existing settings and adds colors and other graphic elements. The Default theme that is shipped with activeCollab is an example of a theme that extends Sandbox and is also something that you can use as an example for creating your own.