.part7_content{

    display: block;

}



.video_hide{

    background: rgba(0,0,0,0.2);

    width: 900px;

    height: 600px;

    position: fixed;

    left: 50%;

    margin-left: -450px;

    top: 50%;

    margin-top: -300px;

}

.video_list{

    position: fixed;

    width: 100%;

    height: 100%;

    background: rgba(0,0,0,0.7);

    z-index: 999;

    left: 0;

    top:0;

}