html5 css3实现图中结构

<!DOCTYPE html>
<html lang="en" >
 <head> 
        
        <title>demo</title>
        
        <style type="text/css">
              *{
                margin:0;
                padding:0;                
               }
           .box {
                 width: 100%;
                 background: green;
                 display: box;
                 overflow: hidden;
                 display:-moz-box; /* Firefox */
              display:-webkit-box; /* Safari and Chrome */
                 -webkit-box-orient:horizontal;
           }
            .item {
               -webkit-box-flex:1;
               -moz-box-flex:1;
             box-flex:1;
             height: 60px;
             margin: 10px;
             background: red;
           }
           .item:first-child {
               -webkit-box-flex:0;
               
             width: 200px;
             margin: 10px;
             background: yellow;
           }
           
             .item:last-child {
               
             margin: 10px;
             background-color: blue;
           }
        </style>
 </head>
 <body >
        <div class="box">
                <div class="item">column 1</div>
                <div class="item">column 2</div>
                <div class="item">column 3</div>
        </div>
        
 </body>
</html>