header .banner {
    background-image: url(../image/banner1.png);   
   }
main .video-class {
    display: flex;
    justify-content: center;
    margin: 57px 0 20px;
}
main .video-class a {
    width: 163px;
    height: 48px;
    display: block;
    background: #dadada;
    color: #a0a0a0;
    text-align: center;
    line-height: 48px;
    text-decoration: none;
}
main .video-list {
    padding: 25px 12.5px;
}
main .video-list img {
    width: 327px;
}

main .video-list p {
    font-size: 16px;
    font-family: SourceHanSansCN, SourceHanSansCN-Regular;
    font-weight: 400;
    color: #2f2f2f;
    letter-spacing: 1px;
    line-height: 40px;
}

main .video-list span {
    color: #666666;
    font-size: 12px;
}
@media screen and (min-width:1450px) {
    .container {
        width: 1450px;
    }
}

@media screen and (max-width: 780px){
    main .video-list {
        padding: 20px;
    }
    main .video-list img {
        width: 100%;
    }
    
    main .video-list p {
        font-size: 16px;
        font-family: SourceHanSansCN, SourceHanSansCN-Regular;
        font-weight: 400;
        color: #2f2f2f;
        letter-spacing: 1px;
        line-height: 40px;
    }
    
    main .video-list span {
        color: #666666;
        font-size: 14px;
    }
}