beyler solda menü var seçtiğim menüye göre sadece sağdaki değişicek nasıl yapabilirim?

HTML
<!doctype html>
<html>
<head>
	<meta charset="UTF-8">
	<title>MCLive</title>
	<link rel="stylesheet" href="assets/style.css">
    <link rel="stylesheet" href="assets/font-awesome-4.3.0/css/font-awesome.min.css" />
    <link rel="stylesheet" href="assets/font-awesome-4.3.0/css/font-awesome.css" />
    <meta http-equiv="X-UA-Compatible" content="IE=9" >
</head>
<body>
	
	<div class="left">
        
        <div class="logo"><i class="fa fa-twitch fa-2x"></i><div class="cutter"></div></div>
        <ul class="menu">
            <li><a href=""><i class="fa fa-align-justify"></i></a></li>
            <li><a href=""><i class="fa fa-bell-o"></i></a></li>
            <li><a href=""><i class="fa fa-life-ring"></i></a></li>
            <li><a href=""><i class="fa fa-video-camera"></i></a></li>
            <li><a href=""><i class="fa fa-wrench"></i></a></li>
        </ul>  
        
        <div class="userarea">
            <div class="cutter"></div>
            <i class="fa fa-xing fa-2x" style="color:#fff;"></i>
        </div>
    </div>

    <div class="right">
        
        <iframe src="http://www.twitch.tv/iijeriichoii/embed" frameborder="1" scrolling="yes" height="250px" width="100%"></iframe>
        
        
    </div>
	
</body>
</html>