Customize a design theme A theme is a collection of one or more style sheets (CSS files) that define a consistent look for a set of pages. Before you beginRole required: content_admin or admin About this task Themes can be invoked in any of the following ways. Directly by content pages. As the default theme of a content site. On the configuration page as a global default. Procedure Navigate to Content Management > Design > Themes. Click New. Type a name for the theme and mark it as Active. Right-click the form header and click Save The Style Sheet related list appears. Use the Style Sheet related list to add style sheets to the theme.