#box{
border: 0px solid #000;
width: 760px;
margin: 0 auto;
text-align: center;
}
#left{
width: 33%;
height: 420px;
float: left;
}
#right{
width:33%;
height: 420px;
float: right;
}
#middle{
width: 33%;
height: 420px;
margin: 0 auto;
}