Complete list of reasons why a css file might not be working
Could it be that you have an error in your CSS file? A parenthesis left unclosed, a missing semicolon etc?
Try:
<link type="text/css" rel="stylesheet" href="http://fakedomain.com/smilemachine/html.css" />
If that doesn't work either, then make sure the URL is accessible, and the content is what you are looking for.
Are you sure the stylesheet is loaded? You can see it using the "Net" tab of Firebug on firefox, or on "Network" tab of the Console of your browser.
(If 1 works) can you have a simple sample style and see whether this is getting applied (and visible in the console)?
Firefox can reject a stylesheet if it is not served with a content type of "text/css". (This is separate from the 'type="text/css"' declaration in the HTML.)