O Guia Definitivo do Yii 1.1

Default roles must be declared in the CAuthManager::defaultRoles property. For example,
the following configuration declares two roles to be default roles: authenticated and guest.
return array(
'components'=>array(
'authManager'=>array(
'class'=>'CDbAuthManager',
'defaultRoles'=>array('authenticated', 'guest'),
),
),
);
Because a default role is assigned to every user, it usually needs to be associated with a
business rule that determines whether the role really applies to the user. For example, the
following code defines two roles, authenticated and guest, which effectively apply to
authenticated users and guest users, respectively.
$bizRule='return !Yii::app()->user->isGuest;';
$auth->createRole('authenticated', 'authenticated user', $bizRule);
$bizRule='return Yii::app()->user->isGuest;';
$auth->createRole('guest', 'guest user', $bizRule);
Temas
Theming is a systematic way of customizing the outlook of pages in a Web application. By
applying a new theme, the overall appearance of a Web application can be changed
instantly and dramatically.
In Yii, each theme is represented as a directory consisting of view files, layout files, and
relevant resource files such as images, CSS files, JavaScript files, etc. The name of a
theme is its directory name. All themes reside under the same directory WebRoot/themes.
At any time, only one theme can be active.
Tip: The default theme root directory WebRoot/themes can be configured to be a
different one. Simply configure the basePath and the baseUrl properties of the
themeManager application component to be the desired ones.
Using a Theme
To activate a theme, set the theme property of the Web application to be the name of the
desired theme. This can be done either in the application configuration or during runtime in
controller actions.