.container {
    text-align: center;
}

.intr {
    margin: 4rem 0 13rem;
}

.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;
}

.m-5 {
    margin-right: 5rem;
}

.videocon video {
    width: 100%;
}


/* 宽度小于530px  iphone 5/SE 、678 */

@media screen and (max-width: 530px) {
    .intr {
        margin: 20px 0;
    }
    .introduce {
        margin-bottom: 20px;
    }
    .m-5 {
        margin: 20px 0;
    }
}