圣杯布局

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            padding: 0;
            margin: 0;
        }
        body{
            min-width: 550px;
        }
      .container{
            background-color: red;
            padding-left: 200px;
            padding-right: 150px;
        }
        .center {
            width: 100%;
            background-color: green;
            float: left;
            height: 500px;
        }
        .left{
            width: 200px;
            height: 100px;
            float: left;
            background-color: pink;
            margin-left: -100%;
            position: relative;
            top: 0;
            right: 200px;
        }
        .right{
            width: 150px;
            background-color: purple;
            height: 100px;
            float: left;
            margin-right: -100%;
        }
    </style>
</head>
<body>
<div class="container">
    <div class="center"></div>
    <div class="left"></div>

    <div class="right"></div>
</div>
</body>
</html>
主要思想是：container中设置pl，pr；包裹left，center，right。全部左浮。其中center宽度设置100%，那么left，和right被挤下去了。left通过利用margin-left:-100%，然后再定位，右移。right通过设置margin-right设置-100%，使其在右边。
记得要给body设置最小宽度。最小宽度为：left和right的宽度加上left右移的距离。