* {
padding:0;
margin:0;
}
.box-1 {
width:640px;
height:300px;
margin:40px auto;
border:1px solid chartreuse;
position:relative;
overflow:hidden;
}
.box-1 li {
width:480px;
height:320px;
float:left;
list-style:none;
position:absolute;
border:1px solid white;
overflow:hidden;
}