What is the primary function of Themes in Liferay's architecture?

The primary function of Themes in Liferay's architecture is to shape the visual representation while ensuring functional integrity. Themes are essential components that dictate the look and feel of a Liferay website. They allow developers to create a consistent design and layout, enhancing the user experience across various pages and applications within the portal.

By utilizing themes, developers can apply styles, layouts, and visual elements that reflect branding and usability standards while still maintaining the underlying functionality of the application. This means that while the visual appeal can be customized effectively, the core functionalities of the portal remain intact and operational, ensuring that users have not just a beautiful interface but also a fully functional experience.

Considering the other options, managing user permissions and access relates more to user roles and security rather than presentation. Templates for data storage are not a function of themes since they deal with content management rather than aesthetics. Backend integration concerns database interactions, which is a separate layer of the Liferay architecture focused on data handling rather than the user interface. Thus, defining how a site looks and behaves visually is the central role of Themes in Liferay.