PHP compresses multiple CSS into one css code and caches it_PHP tutorial

/*
Compress multiple CSS files into one and cache for an hour.

Use the same code for Javascript, but replace below "text/css" with "text/javascript" and of course make sure you include .js files instead of .css ones.
*/
ob_start("ob_gzhandler");
header("Content-type: text/css; charset: UTF-8");    
header("Expires: ".gmdate("D, d M Y H:i:s", time() + 60*60)." GMT");

include('somefile.css');
echo "nn";
include('anotherfile.css');
echo "nn";

ob_flush();