<!DOCTYPE html>
<html>
<head>
<style type='text/css'>
#root {
display: table;
border-spacing: 0;
width: 100%;
height: 500px;
}
#root>div {
display: table-cell;
}
#left {
background: red;
width: 25%;
}
#middle {
background: green;
}
#right {
background: blue;
width: 100px;
}
</style>
</head>
<body>
<div id="root">
<div id="left">Left</div>
<div id="middle">Middle</div>
<div id="right">Right</div>
</div>
</body>
</html>