$re = '/:[0-9]+(\/)(.*)(\/)([a-z]+.[a-z]+)/';
$str = 'https://demchdc9scx.dc4ca.siemens.de:4300/Z_OP_APPLICATIONS/_Playground/JobReq/xs/ui/WebContent/CSS/styles.css';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php