qq-mail-float.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
  <style>
 *{background-color:rgba(0,0,0,0.08)}

html,body,div{
	width:100%;
	height:100%;
	margin:0;
}

header{
	height:10%;
	width:100%;
	background-color:red;
	float:right;
}

aside{
	height:90%;
	width:20%;
	float:left;
	background-color:tan;
}

section{
	height:90%;
	width:80%;
	float:right;
	background:violet;
}N 	
  </style>
</head>
<body>
 <div>
 	 <header></header>
	 <aside></aside>
	 <section></section>
 </div>
</body>
</html>