*{
    margin: 0px;
    padding: 0px;
}
.banner{
    width: 100%;
    height: 400px;
    margin: 0px 0px 0px 0px;
}
.banner .lunbo{
    position: relative;
    z-index: 1;
}
.banner .lunbo ul{
    float:left;
    list-style: none;
}
.banner .lunbo ul li{
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    /* 这里实现淡入淡出的关键 */
    transition: all .6s;
}
.banner .lunbo ul li.active{
    display: block;
    opacity: 1;
}

/* 小圆点 */

.dot .spot{
    list-style: none;
    padding-top: 290px;
    margin-left: 480px;
    width: 300px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: space-around;
    z-index: 999;
}
.dot .spot li{
    width: 10px;
    height: 10px;
    border-radius: 50%;
    box-shadow: inset 0px 2px 5px -2.5px #000,inset 0px 1px 3px -1px #000000;
    background-color: #e4e4e4;
    z-index: 999;
}
.dot .spot .active{
    background-color: #3b3b3b;
}