if (is_win) {
	
	//include supplemental style sheets as necessary for different browser configurations; these should combine with styles already defined in main style sheets
	if(is_nav4) {
		document.write('<link href="http://gumc.georgetown.edu/includes/style_ns-win.css" rel="stylesheet">');
		}
}
else if (is_mac) {
	if(is_nav4) {	
		document.write('<link href="http://gumc.georgetown.edu/includes/style_ns-mac.css" rel="stylesheet">');
	}

}