<html>
<head>
<style type="text/css">
#one {
width: 100px;
height: 100px;
background-color: #00FF00;
}
#two {
height: 50px;
background-color: red;
</style>
</head>
<body>
<div id="one"></div>
<div id="two"></div>
</body>
</html>