O Guia Definitivo do Yii 1.1

Note: Theme name is case-sensitive. If you attempt to activate a theme that does not
exist, Yii::app()->theme will return null.
Creating a Theme
Contents under a theme directory should be organized in the same way as those under
the application base path. For example, all view files must be located under views, layout
view files under views/layouts, and system view files under views/system. For example, if
we want to replace the create view ofPostController with a view in the classic theme, we
should save the new view file asWebRoot/themes/classic/views/post/create.php.
For views belonging to controllers in a module, the corresponding themed view files should
also be placed under the views directory. For example, if the aforementioned
PostController is in a module named forum, we should save the create view file as
WebRoot/themes/classic/views/forum/post/create.php. If the forum module is nested in
another module named support, then the view file should beWebRoot/themes/classic/
views/support/forum/post/create.php.
Note: Because the views directory may contain security-sensitive data, it should be
configured to prevent from being accessed by Web users.
When we call render or renderPartial to display a view, the corresponding view file as well
as the layout file will be looked for in the currently active theme. And if found, those files
will be rendered. Otherwise, it falls back to the default location as specified by viewPath
and layoutPath.
Tip: Inside a theme view, we often need to link other theme resource files. For
example, we may want to show an image file under the theme's images directory.
Using the baseUrl property of the currently active theme, we can generate the URL for
the image as follows,
Yii::app()->theme->baseUrl . '/images/FileName.gif'
Below is an example of directory organization for an application with two themes basic and
fancy.