.about-us {
    min-height: 600px;
    margin-bottom: 25px;
    padding-bottom: 50px;
}

.about-us-content {
    font-size: 16px;
    margin-top: 26px;
}

.about-us-content p {
    margin-top: 10px;
    text-indent: 2em;
    text-align: left;
    line-height: 1.8;
}

.about-us-content-video {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 30px;
}
.about-us-content-img {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 30px;
}

.about-us-content-video video {
    width: 720px;
    height: 480px;
}


.about-us-content-img img {
    width: 720px;
    height: 480px;
}

@media screen and (max-width: 900px) {
    .about-us-content-video video{
        width: 6rem;
        height: 4rem;
    }
    .about-us-content-img img{
        width: 6rem;
        height: 4rem;
    }
    .about-us-content{
        font-size: .35rem;
    }
    .product_topBox_left{
        display: none;
    }
    .product_topBox_right{
        width:100%;
        margin-left:0px !important;
    }
    .ptr_title{
        width:100%;
    }
    .ptr_list{
        width:100% !important;
    }
    .ptr_btn{
        margin-top:0.2rem !important; 
    }
}