.video-list {
    margin: 0 -15px;
}
.video-list .item {
    width: 25%;
    padding: 0 15px;
}
.video-list .item:nth-child(4n+1) {
    clear: left;
}
.video-list .box {
    max-width: 300px;
    margin: 0 auto 50px;
    position: relative;
}
.video-list .box .cover{
    font-size: 0;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    width: 100%;
    height: 100%;
    z-index: 30;
}
.video-list .pic {
    position: relative;
    overflow: hidden;
}
.video-list .txt {
    position: relative;
    padding: 15px 0 0;
}
.video-list .name {
    position: relative;
    height: 55px;
    margin: 0;
    font-size: 18px;
    color: #555555;
    font-weight: 500;
    letter-spacing: 0.35px;
    line-height: 1.45;
    top: 7px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    transition: all 0.3s ease;
}
.video-list .box:hover .name {
    color: #777777;
}
.video-list .description {
    position: relative;
    color: #999;
    font-size: 14px;
    letter-spacing: 0.35px;
    line-height: 1.65;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    height: 65px;
    margin: 20px 0;
    transition: all 0.3s ease;
}
.video-list .box:hover .description {
    color: #777777;
}
.video-header {
    max-width: 1280px;
    margin: 0 auto;
    border-bottom: solid 2px #ddd;
    position: relative;
    padding: 0 0 15px;
    line-height: 1.5;
}
.video-header .title {
    margin-top: 10px;
    font-weight: 500;
    color: #555;
    font-size: 22px;
    margin: 0 0;
    display: block;
}
.video-detail {
    padding: 30px 0;
}
.video-detail  {
    max-width: 1280px;
    margin: 0 auto;
}
.video_box{
    background: #f6f6f6;
    margin-bottom: 15px;
}
.video_box .video{
    max-width: 800px;
    margin: auto;
    line-height: 0;
}
@media screen and (max-width: 1280px) {
    .video-list {
        margin: 0 -10px;
    }
    .video-list .item {
        padding: 0 10px;
    }
}
@media screen and (max-width: 1000px) {
    .video-list .item {
        width: 50%;
    }
    .video-list .item:nth-child(4n+1) {
        clear: none;
    }
    .video-list .item:nth-child(2n+1) {
        clear: left;
    }
    .video-list .item:nth-child(odd){
        border-left:none;
    }
    .video-list .name {
        font-size: 16px;
        height: 45px;
    }
    .video-header .title {
        font-size: 18px;
    }
}
@media screen and (max-width: 767px) {
    .video-list .box {
        margin: 0 auto 30px;
    }
}
@media screen and (max-width: 580px) {
    .video-list li+li {
        border-left: none;
    }
    .video-header .title{
        float: none;
        width: 100%;
        padding-right: 0;
    }
}