Themes control the look and feel of your Discovery Framework application.
Themes are hot deployable plugins that you can use to customize the appearance of your application. By using your own theme, your Discovery Framework application can adhere to the look-and-feel standards which may be used across all of the Web sites and Web applications in your company's infrastructure.
http://www.liferay.com/downloads/liferay-portal/community-plugins
Your application developer can also create customized themes for your application. For information on theme development, see the Liferay Developer's Guide, which is available from the Liferay Web site.
To apply an existing theme to a page:
If the new theme was successfully applied, you will see this message:
Note that each page can have a different theme.