I set "height" CSS property in percent (%) for div element but html render noting. But if I set "height" CSS property in length values, like px, cm, etc it works. Can any one help me?
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<div style="width: 40%; height: 40%; background-color: #565; ">
</div>
</body>
</html>