I suppose this is a common problem. I put in the link statement and the first CSS file. They are not exactly huge steps, and I reran the main HTML file with validator to check the link was ok.
Absolutely zilch. The page is as serify as a very seriffy page. Tried exiting IE. Tried Chrome. Nothing.
The problem is that there appears to be nothing in the way of debug help. Did it not like a file name? Something in the CSS file? The problem is: When it doesn't work you don't get a clue why or any means to find out.