CSS theme support Themes give the user interface a specific look and feel by using different color combinations. System administrators can create themes or customize the existing themes for an instance. To see existing themes, navigate to System UI > Themes. Activating CSS theme supportThere are different plugins that activate CSS themes support.Enable the theme picker (UI15)The theme picker adds a field to the system menu that allows the user to quickly switch between CSS themes during the current browser session.Select a themeYou can switch between different themes for the user interface.Configure a company themeYou can configure a default CSS theme for a particular company in UI15. The theme appears for all users associated with the company unless they select a different theme. Create or customize a themeYou can create themes or customize existing themes.Default CSS stylesYou can use CSS styles to control the appearance of elements in a theme.