SETTING HEIGHT OF DIV TO 100%
Run 
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>CSS</title>
<style>   
      .container {
		border: 3px solid blue;
        height: 100vh;
		text-align: center;
      }
</style>
</head>
<body>
	  <div class="container">
	    <h2>The div with height of the height of browser </h2>
	</div>
</body>
</html>