Internet Explorer (you knew it’d come up eventually) doesn’t deal well with specifying media types – it chokes. Basically, IE (versions 4-7) try to read the media type like it were part of the file name, causing the whole thing to come crashing down. As such, if you don’t want your CSS to have a default media type of “all,” you’re probably better off using a combination of the <link> tag and imports – specifying a media type in your link, and then importing the appropriate CSS within the file you’re linking to. I haven’t yet heard if IE8 suffers from this same problem (if you happen to know, please enlighten me in the comments!).

[http://www.cssnewbie.com/css-import-rule/]