.bg{
    position: absolute;
    width: 100%;
    /*height: 100%;*/
    background: rgba(0,0,0,.4);
    display: none;
    transition: all 500ms;
    top: 0;
    /*z-index: 9999;*/
}
.video-container{
    position: relative;
    width: 70%;
    z-index: 1002;
    left: 15%;
}
.video-container .teaching-video{
    position: absolute;
}
.video-container img{
    position: absolute;
    z-index: 9999;
    right: 0;
}
.teaching-video-container {
    display: flex;
    flex-wrap: wrap;
    width: 90%;
    margin: 0 auto;
}
.teaching-video-card{
    width: 23.5%;
    position: relative;
    padding-bottom: 13.22%;
    margin-bottom: 35px;
    color: #fff;
}
.teaching-video-card:nth-child(4n-2){
    margin: 0 2% 35px;
}
.teaching-video-card:nth-child(4n-1){
    margin-right: 2%;
}

.teaching-video-card .video-background{
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
}
.teaching-video-card .video-title{
    position: absolute;
    width: 60%;
    left: 24px;
    font-size: 18px;
    line-height: 26px;
    right: 24px;
    top: calc(50% - 30px);
    /*overflow: hidden;*/
    /*text-overflow: ellipsis;*/
    /*-webkit-line-clamp: 2;*/
}
.teaching-video-card .video-time{
    position: absolute;
    top: 75%;
    left: 24px;
}
.teaching-video-card .video-playBtn{
    position: absolute;
    width: 60px;
    height: 60px;
    right: 24px;
    top: calc(50% - 30px);
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
}