This recipe details the steps involved in enabling users to choose which theme they wish to use when they are viewing the site. For example, users with accessibility issues might prefer to view the site using a high-contrast theme, or those viewing the site via monitors with low resolutions might prefer a theme which uses a fluid layout.

Drupal's flexible approach to themes includes the ability to allow theme-specific block arrangements. As a result, this allows us to, for example, have a separate theme for site contributors with, perhaps, an extra sidebar equipped with a contributor-specific block arrangement.