<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
    		*{
    			margin: 0;
    			padding: 0;
    		}
    		html,body{
    			width: 100%;
    			height: 100%;
    		}
    		.c1{
    			width: 90%;
    			height: 90%;
    		}
    </style>
</head>
<body>
<div class="c1"></div>
</body>
</html>