.wrap {
width:900px;
height:300px;
margin:10px auto;
border:1px solid #666
}
.wrap .conter {
height:100%;
width:100px;
background:#ff0000;
float:left;
border-right:1px solid #000;
overflow:hidden;
transition:0.5s
}
.wrap .xuan {
transition:0.5s;
width:394px
}