.banner{
    width: 100%;
    height:455px;
    overflow: hidden;
    position: relative;
}
.banner-box{
    height:455px;
}
.banner-box:after{
    content: '';
    display:block;
    clear: both;
}
.banner li{
    width: 100%;
    height:100%;
    float: left;
}
.banner li img{
    display: block;
    width: 100%;
    height: 100%;
}
.button-box{
    width: 120px;
    height:20px;
    display:flex;
    justify-content: space-around;
    position: absolute;
    left: 0;
    right: 0;
    bottom: 30px;
    margin:auto;
    z-index: 50;
}
.button-item{
    width: 20px;
    height: 20px;
    border-radius:50%;
    background-color:#fff;
    cursor: pointer;
    opacity:0.7;
}