var agent = navigator.userAgent;
	var appver = navigator.appVersion;
	var nav = navigator.appName;
	var plf = null;
	var ver = null;
	if(agent.indexOf('Mac') != -1){
plf = "Mac";
	}else if(agent.indexOf('Win') != -1){
plf = "Win";
	}else{
plf = "other";
	}
	if(agent.indexOf('MSIE') == -1){
ver = appver.charAt(0);
if(nav == "Netscape"){
	 nav = "Netscape";
 }
	}else{
 ver = agent.charAt(agent.indexOf('MSIE') + 5);
 nav = "MSIE";
	}
	var ms = navigator.appVersion.indexOf("MSIE");
	var ie4 = (ms>0) && (parseInt(navigator.appVersion.substring(ms+5, ms+6)) >= 4);
	var winie4 = (plf == "Win") && (ms>0) && (parseInt(navigator.appVersion.substring(ms+5, ms+6)) >= 4);
	var macie5 =  (plf == "Mac") && (ms>0) && (parseInt(navigator.appVersion.substring(ms+5, ms+6)) >= 5);
	var nesc = navigator.appName.lastIndexOf("Netscape"); //一致した位置(0)を返す
	var nesc4 = (nesc >= 0) && (parseInt(navigator.appVersion.substring(0,2)) >= 4);
	var MacMozilla =  (plf == "Mac") && (nav == "Mozilla");
<!-- 以下のブラウザ条件箇所にスタイルを書き込んでください。-->
	if (plf == "Mac" ) {
	document.write("<link rel='stylesheet' href='css/mac.css'>");
	} else{
	document.write("<link rel='stylesheet' href='css/win.css'>");
	}