Joomla! 2.5 Menu Manager: Link CSS Style

To assign a custom CSS class to a Joomla menu link

1. From the Joomla Admin menu, select Menus > Main Menu (or whatever menu you want to edit).
2. Click the menu link to which you want to assign a custom CSS class.
3. From the menu options on the right side of the page, click Link Type Options.
   
   
4. In the Link CSS Style field, enter a CSS class name
   
   IMPORTANT: Use only alpha numerical characters, hyphens, and underscores, but no spaces.
5. Click Save & Close to save your changes.
   
   Joomla adds the custom class to the menu link.
   
   
6. Now you can use a CSS class to create custom formatting for the link you modified. For example, create a CSS class in your css stylesheet; make sure to use the exact same class name you used in the link:
   a.homestyle {color:#fff;font-size:11px;background:#666}