var agt=navigator.userAgent.toLowerCase(); 

var is_major = parseInt(navigator.appVersion); 
var is_minor = parseFloat(navigator.appVersion); 

var is_ie   = (agt.indexOf("msie") != -1); 
var is_mac    = (agt.indexOf("mac")!=-1);


var is_ie5  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );

var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1) 
                && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1) 
                && (agt.indexOf('webtv')==-1)); 

if (is_mac)
	{
		// detect whether its ie5 if so load ie5 specific stylesheet
		
		if(is_ie5)
		{		
			document.write("<LINK REL=stylesheet HREF='mac_ie5.css' TYPE='text/css'>"); 		
		}
		else
		{
			// not ie5 load default mac stylesheet
			document.write("<LINK REL=stylesheet HREF='mac_def.css' TYPE='text/css'>"); 				
		}		
	}
	else
	{
		// we now we aren't using a mac
	
		if(is_ie)
		{
			// we now its using internet explorer
			document.write("<LINK REL=stylesheet HREF='pc_ie.css' TYPE='text/css'>"); 			
		}
		else
		{
			// its netscape or opera
			document.write("<LINK REL=stylesheet HREF='./pc_ns.css' TYPE='text/css'>"); 			
		}
		
		
	}