Themes make it possible to easily switch to different presentations or "look and feel" layers. Within a single .war file, a designer/developer can deliver an integrated package of Velocity or JSPs, Javascript, image, and configuration files that will control all presentation logic and design attributes for a portal community. Liferay Portal comes with a handful of pre-made themes that showcase its versatility:
Different themes can be assigned to specific user community websites or even to a specific page within the website
Users can choose a unique theme for their own personal portal page or for each of the pages
Both Java Server Page (JSP) and Velocity (VM) languages are supported
Velocity based Themes are hot-deployable as .wars (when supported by the application server)
To select a different theme, go to the Look and Feel section in the header bar and choose one of the available themes and a corresponding color scheme. The process is as straightforward as setting a new desktop background in Windows.