.header .header-nav-item:nth-child(9)>a{
    color: #0C5BE2;
}

.about{
    width: 1200px;
    margin: 40px auto 80px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.about .about-video-wrap{
    width: 50%;
    aspect-ratio: 600 / 350;
    position: relative;
    overflow: hidden;
}
.about .about-video-wrap .about-img{
    width: 100%;
    height: 100%;
}
.about .about-video-wrap .about-img img{
    width: 100%;
    height: 100%;
}
.about .about-video-wrap .about-img .about-img-icon{
    position: absolute;
    top: 50%;
    left: 50%;
    width: 42px;
    height: 42px;
    transform: translate(-50%,-50%);
    cursor: pointer;
    z-index: 1;
}
.about .about-video-wrap .about-video{
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 2;
    background-color: #E6E6E6;
    display: none;
}
.about .about-video-wrap .about-video video{
    width: 100%;
    height: 100%;
}
.about .about-text{
    width: calc(50% - 60px);
    padding-left: calc((50% - 600px));
}
.about .about-text .title{
    text-align: left;
}
.about .about-text .title-line{
    margin: 10px 0;
}
.about .about-text .about-text-desc{
    font-size: 14px;
    color: #1A1A1A;
    line-height: 21px;
    margin-top: 40px;
}

@media screen and (min-width: 1000px) and (max-width: 1440px){
    .about{
        width: 900px;
        margin: 30px auto 60px;
    }
    .about .about-text .about-text-desc{
        margin-top: 30px;
    }
}
@media screen and (max-width: 1000px){
    .about{
        width: 700px;
        margin: 30px auto 40px;
    }
    .about .about-text .about-text-desc{
        margin-top: 14px;
        font-size: 12px;
        line-height: 18px;
    }
    .about .about-video-wrap .about-img .about-img-icon{
        width: 36px;
        height: 36px;
    }
}


.partner{
    width: 1200px;
    padding: 20px 0;
    margin: 0 auto;
    background: #202020;
    display: flex;
    position: relative;
    z-index: 1;
}
.partner .partner-item{
    width: 20%;
    cursor: pointer;
}
.partner .partner-item img{
    width: 100%;
}

@media screen and (min-width: 1000px) and (max-width: 1440px){
    .partner{
        width: 900px;
        padding: 15px 0;
    }
}
@media screen and (max-width: 1000px){
    .partner{
        width: 700px;
        padding: 10px 0;
    }
}


.engineering-wrap{
    width: 100%;
    height: 385px;
    position: relative;
    margin-top: -80px;
}
.engineering-wrap .engineering-bg{
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    background: url("../images/about-bg.webp") no-repeat center bottom;
    background-size: cover;
    z-index: -1;
}
.engineering{
    width: 1200px;
    position: absolute;
    left: 50%;
    bottom: 100px;
    transform: translateX(-50%);
    display: flex;
}
.engineering .engineering-item{
    width: 33.33%;
    border-right: 1px solid #FFFFFF;
}
.engineering .engineering-item:last-child{
    border: none;
}
.engineering .engineering-item .engineering-item-num{
    font-family: DIN, DIN;
    font-weight: bold;
    font-size: 50px;
    color: #FFFFFF;
    line-height: 67px;
    text-align: center;
}
.engineering .engineering-item .engineering-item-name{
    font-size: 20px;
    color: #FFFFFF;
    line-height: 22px;
    text-align: center;
    margin-top: 20px;
}

@media screen and (min-width: 1000px) and (max-width: 1440px){
    .engineering-wrap{
        height: 289px;
        margin-top: -60px;
    }
    .engineering{
        width: 900px;
        bottom: 70px;
    }
    .engineering .engineering-item .engineering-item-num{
        font-size: 40px;
        line-height: 45px;
    }
    .engineering .engineering-item .engineering-item-name{
        font-size: 18px;
    }
}
@media screen and (max-width: 1000px){
    .engineering-wrap{
        height: 224px;
        margin-top: -45px;
    }
    .engineering{
        width: 700px;
        bottom: 50px;
    }
    .engineering .engineering-item .engineering-item-num{
        font-size: 36px;
        line-height: 40px;
    }
    .engineering .engineering-item .engineering-item-name{
        font-size: 16px;
    }
}


.certificate{
    width: 1200px;
    margin: 80px auto;
    position: relative;
}
.certificate .certificate-list{
    margin-top: 40px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
}
.certificate .certificate-item{
    width: 24%;
    margin-right: 1.33%;
    cursor: pointer;
    margin-top: 20px;
    float: left;
}
.certificate .certificate-item:nth-child(4n){
    margin-right: 0;
}
.certificate .certificate-item:nth-child(-n+4){
    margin-top: 0;
}
.certificate .certificate-item img{
    width: 100%;
    cursor: pointer;
}


@media only screen and (min-width: 1000px) and (max-width: 1440px) {
    .certificate{
        width: 900px;
        margin: 60px auto;
    }
    .certificate .certificate-list{
        margin-top: 30px;
    }
}
@media only screen and (max-width: 1000px) {
    .certificate{
        width: 700px;
        margin: 40px auto;
    }
    .certificate .certificate-list{
        margin-top: 20px;
    }
}