<html>
<head>
<style>
body{height:100%; margin:0;}
.sidebar{height:100%; display: inline-block; background: red; width:300px;vertical-align:top;}
.content{width: calc(100% - 300px); display:inline-block; background:#eee; height:100%;}
footer{height:100px; background: #aaa;}
</style>
</head>
<body>
<div class="sidebar">sidebar</div><div class='content'>content</div>
<footer>footer</footer>
</body>
</html>
Простой
Простой
