Typical RL definition for skins.

gistfile1.php

<?php
$wgResourceModules['skins.yourskin'] = array(
	'styles' => array(
		'yourskin/yourskin.css' => array( 'media' => 'screen' ),
	),
	'remoteBasePath' => &$GLOBALS['wgStylePath'],
	'localBasePath' => &$GLOBALS['wgStyleDirectory'],
);