destus,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style>
html, body{
height: 100%;
}
body {
position: relative;
margin: 0;
padding: 0;
min-height: 100%;
}
div {
border: 1px solid black;
width: 100%;
box-sizing: border-box;
text-align: center;
}
#header { background-color: #008000;
position: absolute;
top: 0;
height: 1.5em;
}
#content { background-color: #FFD700;
min-height: 100%;
}
#footer { background-color: #00BFFF;
position: absolute;
bottom: 0;
height: 1.5em;
}
</style>
</head>
<body>
<div id="header">Header</div>
<div id="content">Content</div>
<div id="footer">Footer</div>
</body>
</html>