双飞翼布局----利用float和margin实现双飞翼布局

<div id="main-content">
    <div id="main-left">left容器</div>
    <div id="main-right">right容器</div>
    <div id="main-center">center容器</div>
</div>

#main-left,#main-right,#main-center{
    height: 200px;
    color: #fff;
    box-sizing: border-box;
    padding: 10px;
}
#main-left{
    float: left;
    background: blue;
    width: 100px;
}
#main-right{
    float: right;
    background: green;
    width: 100px;
}
#main-center{
    margin: 0 100px;
    background: pink;
}