var yourBrowser = navigator.userAgent.toLowerCase();
	var isMac = yourBrowser.indexOf("mac") != -1;
	
	if(isMac==1) {
	  document.write('<link rel="STYLESHEET" type="text/css" href="enthermics_mac.css">');
	}
	
	else { 
	  document.write('<link rel="STYLESHEET" type="text/css" href="enthermics.css">');
	}