如何实现此布局？
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
*{
margin: 0px;
padding: 0px;
}
html,body{
height: 100%;
}
.top,.buttom{
width: 100%;
height: 50px;
background: #ccc;
}
.middle{
height: calc(100% - 100px);
background: yellow;
}
.left,.right{
width: 100px;
height: 100px;
background: red;
float: left;
}
.center{
width: calc(100% - 200px);
height: 100%;
background: blue;
float: left;
}
</style>
</head>
<body>
<div class="top">1</div>
<div class="middle">2
<div class="left">3</div>
<div class="center">4</div>
<div class="right">5</div>
</div>
<div class="buttom">6</div>
</body>
</html>
