var agt=navigator.userAgent.toLowerCase(); 
var version = parseInt( navigator.appVersion );
var opera = (agt.indexOf("opera") != -1);
var opera7 = (opera && (version >= 7));
var moz = (agt.indexOf("gecko") != -1);
var ie = ((agt.indexOf("msie") != -1) && !moz && !opera);
var ie4 = (ie && (version >= 4));
var nn = ((agt.indexOf("mozilla") != -1) && !ie && !moz && !opera);
var nav4 = (nn && (version >= 4));  
var iswin  = (agt.indexOf("win")!=-1);
var ismac  = (agt.indexOf("mac")!=-1);
var isunix = (agt.indexOf("x11")!=-1);

if (nav4||ie4||moz||opera7|| (!nn && !ie && !moz && !opera)) {

	var isFour = true;

	var styles = "styles/";

	if (iswin) styles += (nn)?"winns.css":"winie.css"; 
	else if (ismac) styles += (nn)?"macns.css":"macie.css";	

	else 		 styles += (nn)?"unix.css":"winie.css";	
	document.write('<LINK REL="stylesheet" HREF="'+styles+'" TYPE="text/css">');

}