if (is.win){
	if (is.ns4){
	document.write('<link rel=stylesheet href="css/style_win-ns.css">');
	}
}
else if (is.mac){
	if (is.ie4){
		document.write('<link rel=stylesheet href="css/style_mac-ie.css">');
	}
	else if (is.ns4){
		document.write('<link rel=stylesheet href="css/style_mac-ns.css">');
	}
}