// convert all characters to lowercase to simplify testing 
var agt=navigator.userAgent.toLowerCase(); 

// *** BROWSER VERSION *** 
var vers = parseInt(navigator.appVersion); 

// *** BROWSER TYPE *** 
var nn = (
	(agt.indexOf('mozilla')!=-1) &&
	(agt.indexOf('gecko')==-1) && (agt.indexOf('compatible')==-1) &&
	(agt.indexOf('opera')==-1) && (agt.indexOf('webtv')==-1)
);
var nav4 = (nn && (vers >= 4));  

var ie = (agt.indexOf("msie") != -1); 
var ie4 = (ie && (vers >= 4));
var moz = (agt.indexOf("gecko") != -1);

// *** PLATFORM ***
var is_win  = (agt.indexOf("win")!=-1);
var is_mac  = (agt.indexOf("mac")!=-1);
var is_unix = (agt.indexOf("x11")!=-1);

// Select the appropriate stylesheet
if (nav4 || ie4 || (!nn && !ie)) {
	var isFour = true;
	var styles = location.protocol + "//www.sgi.co.jp/styles/";
	if 	(is_win) styles += (nn)?"win_ns.css":"win_ie.css";	// Microsoft Windows 
	else if (is_mac) styles += (nn)?"mac.css":"win_ie.css";		// Apple Macintosh
	else 		 styles += (nn)?"unix.css":"win_ie.css";	// UNIX
	document.write('<LINK REL="stylesheet" HREF="' + styles + '" TYPE="text/css">');
}