Joomla Search-Engine-Friendly URLS display an unformatted page

Issue

When Search Engine Friendly URLs are enabled in Joomla, the pages lose their formatting and CSS styles.

Solution

This is most likely caused by an incomplete mod_rewrite configuration.

Follow the steps detailed in the following Joomla article. Take particular note of the requirement to rename htaccess.txt to .htaccess in your /httpdocs directory.

http://docs.joomla.org/How_do_you_implement_Search_Engine_Friendly_URLs_%28SEF%29%3F