.container {
    text-align: center;
}

.intr {
    margin: 4rem 0 4.5rem;
}

.intr .introduce:nth-child(2) {
    margin-bottom: 0;
}

.introduce {
    width: 100%;
    letter-spacing: 1px;
    margin-bottom: 3rem;
    color: #717171;
    font-size: 16px;
    text-align: left;
}

.introduce span {
    color: #E5735B;
}

.arbut {
    padding: 10px 25px;
    display: inline-block;
    text-align: center;
    background-color: #E5735B;
    font-size: 16px;
    color: #ffffff;
    margin-top: 3.5rem;
}

.arbut p {
    margin: 0;
}

.videobox {
    margin-bottom: 13.3rem;
}

.video {
    background-color: #D8D8D8;
    width: 100%;
    height: auto;
    min-height: 100%;
    position: relative;
    padding-bottom: 57%;
    overflow: hidden;
}

.video video {
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
}

.video img {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
    width: 80px;
    height: 80px;
}

.videoname {
    width: 100%;
    font-size: 20px;
    text-align: center;
    margin: 14px 0 20px;
}


/* 宽度小于530px  iphone 5/SE 、678 */

@media screen and (max-width: 530px) {
    .intr {
        margin: 20px 0;
    }
    .introduce {
        margin-bottom: 20px;
    }
    .video {
        height: 280px;
    }
    .video img {
        width: 50px;
        height: 50px;
    }
    .videoname {
        font-size: 16px;
    }
}