The URIid extension makes it possible to create CSS rules based on the site you are visiting. This is useful when specific sites do not render correctly or are simply not visually appealing.
The extension adds an id to the body of each page allowing the id selector to be used in your User Stylesheet (userContent.css) file. For example, when visiting the site “http://www.google.com”, the id “www-google-com” will be added to the body. The stylesheet can then use the #www-google-com selector to apply styles only to that site.