Minifies and combines CSS files into a single HTTP request to reduce overhead and round trips
Change your CSS include scripts from:
<link rel="stylesheet" href="/shared/css/css1.css" />
<link rel="stylesheet" href="/shared/css/css2.css" />
<link rel="stylesheet" href="/shared/css/css3.css" />
to a single include script
<link rel="stylesheet" href="/cssmin/shared/css/css1.css/shared/css/css2.css/shared/css/css3.css" />
Doesn't play well relative links - loading fonts, etc