Server-side scripted CSS?

So I'm sure it should be possible to build your style sheets using asp/php/jsp.... just as you do a normal webpage. So if someone clicks on 'large text' or 'high contrast' you don't have to have loads of css files for every combination but can just change the text size/colour in the stylesheet dynamically.[list=1]
Is this in fact possible?
Is it used much?
Is it recommended?
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Cheers

Yes it's possible - just make sure you send the right content-type header:

<?php
header("Content-type: text/css");
?>

for asp you can just change the extention of the css file and do
<style><!--#include file="style.asp" --></style>
im not sure if you can just leave it as css and put asp inside it, as it is only writing the contents of the file to an asp page anyway. this works the same as the link tag but the generated html has the style generated into it not just linked in client side :p