// my-styles.css
* {
padding: 0;
margin: 0;
}
// load-css.php
$css = 'my-styles.css';
header('Content-type: text/css; charset=utf-8');
echo preg_replace(['//*[sS]*?*//','/s*([;:{},>+]]s*/','/;}/','/r?n/'), ['','1','}',''], file_get_contents($css));