* {
    margin: 0;
    padding: 0;
}
 
.app {
    width: 100%;
    /* margin: 50px 0; */
    text-align: center;
}
 
.app .scroll {
    position: relative;
    display: inline-block;
    width: 100%;
    height: 100%;
}
 
.app .scroll .img {
    display: none;
    width: 100%;
}
 
.app .scroll .current {
    display: block;
}
 
.scroll .lf {
    position: absolute;
    top: 50%;
    left: 10px;
    background-image: url('img/arrow.png');
    background-position: -83px 0;
    width: 41px;
    height: 69px;
    cursor: pointer;
    transform: translateY(-50%);
}
 
.scroll .lr {
    position: absolute;
    top: 50%;
    right: 10px;
    background-image: url('img/arrow.png');
    background-position: -123px 0;
    width: 41px;
    height: 69px;
    cursor: pointer;
    transform: translateY(-50%);
}
 
.dots {
    position: absolute;
    bottom: 15px;
    right: 20px;
    width: 160px;
}
 
.dots>span {
    display: inline-block;
    box-sizing: border-box;
    width: 11px;
    height: 11px;
    border: 3px solid rgba(204, 204, 204, 0.2);
    border-radius: 15px;
    cursor: pointer;
}
 
.dots>span:not(:last-child) {
    margin-right: 5px;
}
 
/* 小圆点的颜色 */
.dots .square {
    background: #f46;

}