双飞翼布局

<style>
            .body{
                width: 1000px;
            }
            .box{
                width: 100%;
                height: 500px;
                float: left;
                background: cadetblue;
            }
            .left{
                width: 200px;
                height: 500px;
                float: left;
                background: firebrick;
                margin-left: -100%;
            }
            .right{
                width: 200px;
                height: 500px;
                float: right;
                background: firebrick;
                margin-left: -100%;
            }
            .center{
                background: gold;
                height: 500px;
                margin: 0 222px;
            }
        </style>
                <div class="body">
            <div class="box">
                <div class="center">dhgdf</div>
            </div>
            <div class="left">dggs</div>
            <div class="right">sdfsef</div>
        </div>