.nav a:first-of-type {
    background-color: #fff;
    color: #333;
}

.nav a:first-of-type:hover {
    background-color: #FF6600;
    color: #fff;
}

.nav a:last-of-type {
    background-color: #FF6600;
    color: #fff;
}

body {
    background-color: #fbfbfb
}

.introduction {
    width: 1140px;
    height: 380px;
    margin: 0 auto;
    position: relative;
}

.content01 {
    position: absolute;
    top: 80px;
    left: 3px;
    z-index: 99;
}

.introduction_title_area {
    width: 417px;
    height: 300px;
    background-color: #fff;
    position: absolute;
    top: 80px;
    left: 0;
    border-radius: 12px
}

.introduction_title {
    width: 379px;
    height: 161px;
    position: absolute;
    top: 160px;
    left: 70px;
    text-align: right;
}

.introduction_name {
    font-size: 48px;
    line-height: 64px;
    color: #FF6600
}

.introduction_en {
    margin-top: 16px;
    margin-bottom: 10px;
}

.introduction_content {
    width: 630px;
    height: 268px;
    position: absolute;
    top: 112px;
    right: 0;
    font-size: 14px;
    line-height: 26px;
    color: #666;
}

.introduction_item {
    width: 630px;
    height: 52px;
    margin-bottom: 20px;
    position: relative;
}

.introduction_item:last-of-type {
    margin-bottom: 0;
}

.circle {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: #666;
    position: absolute;
    left: 0;
    top: 11px;
}

.introduction_item li {
    display: block;
    width: 608px;
    font-size: 14px;
    line-height: 26px;
    color: #666;
    position: absolute;
    left: 22px;
    top: 0;
    text-align: justify;
}

.introduction_section2 {
    background: url("../img/aboutus_back01.png") no-repeat;
    background-size: 100% 100%;
}

.introduction2 {
    height: 1060px;
    width: 1130px;
    margin: 0 auto;
    position: relative;
}

.content02 {
    position: absolute;
    top: 0;
    right: 0;
    z-index: 99;
}

.introduction_title2 {
    width: 379px;
    height: 161px;
    position: absolute;
    top: 300px;
    right: 10px;
    text-align: right;
}

.team01 {
    position: absolute;
    top: 192px;
    left: 0;
}

.team02 {
    position: absolute;
    top: 549px;
    left: 0;
}

.team03 {
    position: absolute;
    top: 549px;
    left: 310px;
}

.company_introduction {
    width: 466px;
    height: 182px;
    position: absolute;
    top: 501px;
    right: 10px;
    text-align: left;
    font-size: 14px;
    line-height: 26px;
    color: #666;
    text-align: justify;
}

.qualifications {
    height: 632px;
    width: 1200px;
    margin: 0 auto;
    position: relative;
}

.content03 {
    position: absolute;
    top: -291px;
    right: 50px;
    z-index: 99;
}

.qualifications_title {
    width: 415px;
    height: 328px;
    position: absolute;
    top: -130px;
    left: 34px;
    text-align: right
}

.certificate_swiper_container {
    width: 1200px;
    height: 446px;
    position: absolute;
    top: 81px;
    left: 0px;
}

.prev-button {
    position: absolute;
    top: 193px;
    left: 0;
}

#certificate_swiper {
    width: 1040px;
    height: 446px;
    position: absolute;
    top: 0;
    left: 80px;
}

#certificate_swiper .swiper-slide {
    border-radius: 12px
}

.next-button {
    position: absolute;
    top: 193px;
    right: 0;
}

.contactus_section {
    background: url("../img/aboutus_back02.png") center no-repeat;
    background-size: 100% 100%;
}

.contactus {
    height: 566px;
    width: 990px;
    margin: 0 auto;
    position: relative;
}

.content04 {
    position: absolute;
    top: -90px;
    right: 15px;
    z-index: -1;
}

.contact_wechat {
    position: absolute;
    top: 252px;
    right: 486px;
    z-index: 1;
}

.contactus_title {
    width: 379px;
    height: 328px;
    position: absolute;
    top: 180px;
    right: 10px;
    text-align: right
}

.swiper-slide {
    text-align: center;
    font-size: 18px;
    background: #fff;
    /* Center slide text vertically */
    display: -webkit-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    -webkit-justify-content: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    -webkit-align-items: center;
    align-items: center;
}

.certificate {
    width: 328px;
    height: 446px;
    border-radius: 12px;
}

.contactus_content {
    width: 500px;
    height: 216px;
    position: absolute;
    bottom: 88px;
    left: 0;
}

.contactus_item {
    font-size: 16px;
    line-height: 21px;
    margin-bottom: 48px;
    display: flex;
    align-items: center;
}

.big_img {
    z-index: 999;
    background-color: #fff;
    position: fixed
}

#big_img {
    z-index: 999;
}

#mask {
    width: 100%;
    height: 100%;
    display: none;
    position: fixed;
    top: 0px;
    filter: alpha(opacity=30);
    background-color: #000;
    z-index: 99;
    left: 0px;
    opacity: 0.3;
    -moz-opacity: 0.3;
}