.banner{position:relative;}
.banner-title {
    position: absolute;
    left: 50%;
    top: 50%;
    text-align: center;
    transform: translate(-50%,-50%);
    color: #fff;
}
.engTitle {
    font-size: 1.25rem;
    text-transform: uppercase;
    line-height: 1.2;
    position: relative;
    z-index: 1;
}
.chTitle {
    font-weight: bold;
    font-size: 2.5rem;
}
.introduct {
    font-size: 3rem;
    font-weight: bold
}
.desc {
    font-size: 1rem;
    margin-top: 2rem;
}

.video-title {
    font-weight: bold;
    font-size: 1.5rem;
    margin: 2rem 0;
}
.navigation {
    display: flex;
    justify-content: space-between;
    margin: 3rem 0 2rem;
}
.sub-title{font-weight:bold;margin-top:.5rem;font-size:1rem}
.thumbs{position:relative;line-height:0}
.video-wrap{padding:5rem 10%}
.video-list{display:flex;justify-content:space-between;flex-wrap:wrap}
.video-item{width:48%;margin-bottom:2rem}