.header .header-nav-item:nth-child(5)::after{
    content: '';
}


.about{
    width: 100%;
    background: #F6F6F6;
}
.about .about-content{
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.about .about-video-wrap{
    width: 50%;
    aspect-ratio: 960 / 560;
    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: 80px;
    height: 80px;
    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-content .about-text{
    width: calc(50% - 60px);
    padding: 20px 0 20px calc((50% - 600px));
}
.about .about-content .about-text .title{
    text-align: left;
}
.about .about-content .about-text .about-text-desc{
    font-size: 14px;
    color: #1A1A1A;
    line-height: 21px;
    margin-top: 30px;
}
.about .about-content .about-engineering{
    margin-top: 50px;
    display: flex;
    justify-content: space-between;
}
.about .about-content .about-engineering .about-engineering-item .about-engineering-item-num{
    font-weight: bold;
    font-size: 30px;
    color: #1A1A1A;
    line-height: 33px;
}
.about .about-content .about-engineering .about-engineering-item:hover .about-engineering-item-num{
    color: #DA251C;
}
.about .about-content .about-engineering .about-engineering-item .about-engineering-item-num span{
    font-size: 16px;
}
.about .about-content .about-engineering .about-engineering-item .about-engineering-item-name{
    font-size: 12px;
    color: #999999;
    line-height: 14px;
    margin-top: 10px;
}

@media screen and (min-width: 1000px) and (max-width: 1440px){
    .about .about-content .about-text{
        padding-left: calc( 50% - 450px );
    }
    .about .about-content .about-text .about-text-desc{
        font-size: 12px;
        line-height: 16px;
        margin-top: 10px;
    }
    .about .about-content .about-engineering{
        margin-top: 10px;
    }
    .about .about-content .about-engineering .about-engineering-item .about-engineering-item-num{
        font-size: 24px;
        line-height: 36px;
    }
    .about .about-content .about-engineering .about-engineering-item .about-engineering-item-name{
        margin-top: 5px;
    }
}
@media screen and (max-width: 1000px){
    .about .about-content{
        display: block;
    }
    .about .about-content .about-text{
        width: 700px;
        margin: 0 auto;
    }
    .about .about-content .about-text .about-text-desc{
        font-size: 12px;
        line-height: 16px;
        margin-top: 5px;
    }
    .about .about-content .about-engineering{
        margin-top: 5px;
    }
    .about .about-content .about-engineering .about-engineering-item .about-engineering-item-num{
        font-size: 20px;
        line-height: 30px;
    }
    .about .about-content .about-engineering .about-engineering-item .about-engineering-item-name{
        margin-top: 0;
        font-size: 10px;
    }
    .about .about-video-wrap{
        width: 700px;
        margin: 0 auto;
    }
}


.certificate{
    width: 1200px;
    margin: 80px auto;
    position: relative;
}
.certificate .certificate-list{
    margin-top: 40px;
    display: flex;
    flex-wrap: wrap;
}
.certificate .certificate-item{
    width: 24%;
    margin-right: 1.33%;
    cursor: pointer;
    margin-top: 30px;
    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;
    }
}

.partner-wrap{
    width: 100%;
    padding: 80px 0;
    background-color: #F8F8FA;
    background-repeat: no-repeat;
    background-position: center bottom;
}
.partner{
    width: 1200px;
    margin: 0 auto;
}
.partner .partner-list{
    display: flex;
    margin-top: 40px;
    flex-wrap: wrap;
}
.partner .partner-list .partner-item{
    width: 20%;
    aspect-ratio: 2 / 1;
    cursor: pointer;
    overflow: hidden;
}
.partner .partner-list .partner-item img{
    width: 100%;
    height: 100%;
    transition: all 0.5s ease;
}
.partner .partner-list .partner-item:hover img{
    transform: scale(1.1);
}



@media only screen and (min-width: 1000px) and (max-width: 1440px) {
    .partner-wrap{
        padding: 60px 0;
    }
    .partner{
        width: 900px;
    }
    .partner .partner-list{
        margin-top: 30px;
    }
}
@media only screen and (max-width: 1000px) {
    .partner-wrap{
        padding: 40px 0;
    }
    .partner{
        width: 700px;
    }
    .partner .partner-list{
        margin-top: 20px;
    }
}