1.Create minify.php, paste this below code and save.
<?php
header('Content-type: text/css');
ob_start("compress");
function compress($buffer) {
$buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);
/* remove tabs, spaces, newlines, etc. */
$buffer = str_replace(array("\r\n", "\r", "\n", "\t", ' ', ' ', ' '), '', $buffer);
return $buffer;
}
/* your css files : add one by one */
include("stylesheet.css");
include("common.js");
ob_end_flush();
?>
2. In index.php or header file inclusions call the minify.php like below
<!doctype html><html><head><link rel="stylesheet" href="minify.php" type="text/css" media="all" /></head><body> <div>Hello</div></body></html>