@media (max-width: 600px) {
    main .content-gas {
        overflow: hidden;
    }

    main .topbg {
        width: 100%;
        height: auto;
        color: #181818;
        z-index: -99999;
        position: relative;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        background-position-x: 65%;
    }

    main .topbg .sxtitcen {
        /* width: 1200px; */
        height: 300px;
        margin: auto;
        padding-top: 100px;
        position: relative;
    }

    main .topbg .sxtitcen p {
        /* width: 396px; */
        height: 32px;
        font-weight: 400;
        font-size: 16px;
        color: #FFFFFF;
        line-height: 32px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        z-index: -99999;
        display: none;
    }

    main .topbg .sxtitcen h2 {
        font-weight: 700;
        font-size: 24px;
        color: #FFFFFF;
        line-height: 63px;
        font-style: normal;
        text-transform: none;
        margin: 0;
        text-align: center;
        display: none;
    }

    main .select-nav {
        overflow: hidden;
    }

    main .select-nav .nav {
        display: flex;
    }

    main .select-nav .nav .nav-item {
        flex: 1;
        font-size: 14px;
    }

    main .introduce {
        width: 100%;
        min-height: 1000px;
        background: #FFFFFF;
    }

    main .introduce div {
        /* width: 1200px; */
        min-height: 1000px;
        margin: auto;
        text-align: center;
    }

    main .introduce div h3 {
        width: 100%;
        min-height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 100px;
        margin-bottom: 0px;
        padding-bottom: 0px;
    }

    main .introduce div p {
        /* width: 100%; */
        min-height: 70px;
        font-weight: 400;
        font-size: 16px;
        color: #181818;
        line-height: 35px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        padding: 3%;
    }

    main .introduce div img {
        margin-top: 100px;
        width: 95%;
        height: auto;
        max-width: 800px;
        max-height: 800px;
        margin-bottom: 50px;
    }

    main .feature {
        width: 100%;
        min-height: 1880px;
        background: #F5F7FA;
    }

    main .feature div {
        /* width: 1200px; */
        min-height: 1336px;
        margin: auto;
        text-align: center;
    }

    main .feature h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 0px;
        padding-top: 100px;
        margin-bottom: 80px;
    }

    main .feature ul {
        width: 95%;
        overflow: hidden;
        margin: auto;
        padding: 0;
    }

    main .feature ul li {
        width: 386px;
        height: 246px;
        border-radius: 4px 4px 4px 4px;
        float: none;
        background-repeat: no-repeat;
        background-position: center;
        background-color: #FFFFFF;
        background-position-y: 40px;
        background-size: 40px 40px;
        box-sizing: border-box;
        margin: auto;
        margin-bottom: 5%;
        display: block;
        position: relative;
    }

    main .feature ul li h4 {
        height: 26px;
        font-weight: 700;
        font-size: 18px;
        color: #181818;
        line-height: 26px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-bottom: 0px;
        position: absolute;
        top: 30%;
        left: 40%;
    }

    main .feature ul li .special {
        margin-top: 65px;
    }

    main .feature ul li p {
        height: 40px;
        font-weight: 400;
        font-size: 14px;
        color: #4B5B76;
        line-height: 20px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 40px;
        position: absolute;
        top: 40%;
        /* left: 27%; */
        width: 100%;
    }

    main .dh {
        width: 100%;
        height: 64px;
        background: #FFFFFF;
        box-shadow: 0px 4px 10px 0px rgba(39, 111, 232, 0.05);
    }

    main .dh ul {
        width: 100%;
        height: auto;
        margin: auto;
    }

    main .dh ul li {
        width: 50%;
        text-align: center;
        font-weight: 400;
        font-size: 14px;
        color: #181818;
        line-height: 64px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        float: left;
    }

    main .dh ul li a {
        color: #181818;
    }

    main .dh ul .dh-on a {
        color: #0073FF;
        /* padding-bottom: 20px;
        border-bottom: 2px solid #0073FF; */
    }

    main .dh ul .dh-on samp {
        margin: auto;
        display: block;
        width: 40px;
        height: 3px;
        background: #0073FF;
    }

    main .dh ul li a:hover {
        color: #0073FF;
    }

}

@media (min-width: 600px) and (max-width: 767px) {
    main .content-gas {
        min-height: 1000px;
    }

    main .topbg {
        width: 100%;
        height: 530px;
        color: #181818;
        z-index: -99999;
        position: relative;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        background-position-x: 65%;
    }

    main .topbg .sxtitcen {
        /* width: 1200px; */
        height: 300px;
        margin: auto;
        padding-top: 130px;
        padding-left: 50px;
        position: relative;
    }

    main .topbg .sxtitcen p {
        /* width: 396px; */
        height: 32px;
        font-weight: 400;
        font-size: 22px;
        color: #FFFFFF;
        line-height: 32px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        z-index: -99999;
    }

    main .topbg .sxtitcen h2 {
        /* width: 512px; */
        height: 186px;
        font-weight: 700;
        font-size: 64px;
        color: #FFFFFF;
        line-height: 93px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        margin: 0px;
        z-index: -99999;
    }

    main .introduce {
        width: 100%;
        min-height: 1000px;
        background: #FFFFFF;
    }

    main .introduce div {
        width: 80%;
        min-height: 1000px;
        margin: auto;
        text-align: center;
    }

    main .introduce div h3 {
        width: 100%;
        min-height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 100px;
        margin-bottom: 0px;
        padding-bottom: 0px;
    }

    main .introduce div p {
        /* width: 100%; */
        min-height: 70px;
        font-weight: 400;
        font-size: 16px;
        color: #181818;
        line-height: 35px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        padding: 3%;
    }

    main .introduce div img {
        margin-top: 100px;
        width: 95%;
        height: auto;
        max-width: 800px;
        max-height: 800px;
        margin-bottom: 50px;
    }

    main .feature {
        width: 100%;
        min-height: 980px;
        background: #F5F7FA;
    }

    main .feature div {
        /* width: 1200px; */
        min-height: 1136px;
        margin: auto;
        text-align: center;
    }

    main .feature h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 0px;
        padding-top: 100px;
        margin-bottom: 80px;
    }

    main .feature ul {
        width: 95%;
        min-height: 600px;
        margin: auto;
    }

    main .feature ul li {
        width: 47%;
        height: 246px;
        border-radius: 4px 4px 4px 4px;
        background-repeat: no-repeat;
        background-position: center;
        background-color: #FFFFFF;
        background-position-y: 40px;
        background-size: 40px 40px;
        box-sizing: border-box;
        margin: auto;
        margin-bottom: 5%;
        margin-right: 3%;
        display: block;
        position: relative;
        float: left;
    }

    main .feature ul li h4 {
        height: 26px;
        font-weight: 700;
        font-size: 18px;
        color: #181818;
        line-height: 26px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-bottom: 0px;
        position: absolute;
        top: 30%;
        left: 40%;
    }

    main .feature ul li .special {
        margin-top: 65px;
    }

    main .feature ul li p {
        height: 40px;
        font-weight: 400;
        font-size: 14px;
        color: #4B5B76;
        line-height: 20px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 40px;
        position: absolute;
        top: 40%;
        width: 100%;
        /* left: 27%; */
    }

    main .dh {
        width: 100%;
        height: 64px;
        background: #FFFFFF;
        box-shadow: 0px 4px 10px 0px rgba(39, 111, 232, 0.05);
    }

    main .dh ul {
        width: 100%;
        height: auto;
        margin: auto;
    }

    main .dh ul li {
        width: 50%;
        text-align: center;
        font-weight: 400;
        font-size: 20px;
        color: #181818;
        line-height: 64px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        float: left;
    }

    main .dh ul li a {
        color: #181818;
    }

    main .dh ul .dh-on a {
        color: #0073FF;
        /* padding-bottom: 20px;
        border-bottom: 2px solid #0073FF; */
    }

    main .dh ul .dh-on samp {
        margin: auto;
        display: block;
        width: 40px;
        height: 3px;
        background: #0073FF;
    }

    main .dh ul li a:hover {
        color: #0073FF;
    }

}

@media (min-width: 768px) {
    main .content-gas {
        min-height: 1000px;
    }

    main .topbg {
        width: 100%;
        height: 530px;
        color: #181818;
        z-index: -99999;
        position: relative;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        background-position-x: 65%;
    }

    main .topbg .sxtitcen {
        /* width: 1200px; */
        height: 300px;
        margin: auto;
        padding-top: 155px;
        padding-left: 60px;
        position: relative;
    }

    main .topbg .sxtitcen p {
        /* width: 396px; */
        height: 32px;
        font-weight: 400;
        font-size: 22px;
        color: #FFFFFF;
        line-height: 32px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        z-index: -99999;
    }

    main .topbg .sxtitcen h2 {
        /* width: 512px; */
        height: 186px;
        font-weight: 700;
        font-size: 64px;
        color: #FFFFFF;
        line-height: 93px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        margin: 0px;
        z-index: -99999;
    }

    main .introduce {
        width: 100%;
        min-height: 1000px;
        background: #FFFFFF;
    }

    main .introduce div {
        width: 80%;
        min-height: 1000px;
        margin: auto;
        text-align: center;
    }

    main .introduce div h3 {
        width: 100%;
        min-height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 100px;
        margin-bottom: 0px;
        padding-bottom: 0px;
    }

    main .introduce div p {
        /* width: 100%; */
        min-height: 70px;
        font-weight: 400;
        font-size: 16px;
        color: #181818;
        line-height: 35px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        padding: 3%;
    }

    main .introduce div img {
        margin-top: 100px;
        width: 95%;
        height: auto;
        max-width: 800px;
        max-height: 800px;
        margin-bottom: 50px;
    }

    main .feature {
        width: 100%;
        min-height: 980px;
        background: #F5F7FA;
    }

    main .feature div {
        /* width: 1200px; */
        min-height: 1136px;
        margin: auto;
        text-align: center;
    }

    main .feature h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 0px;
        padding-top: 100px;
        margin-bottom: 80px;
    }

    main .feature ul {
        width: 85%;
        min-height: 600px;
        margin: auto;
    }

    main .feature ul li {
        width: 47%;
        height: 246px;
        border-radius: 4px 4px 4px 4px;
        background-repeat: no-repeat;
        background-position: center;
        background-color: #FFFFFF;
        background-position-y: 40px;
        background-size: 40px 40px;
        box-sizing: border-box;
        margin: auto;
        margin-bottom: 5%;
        margin-right: 3%;
        display: block;
        position: relative;
        float: left;
    }

    main .feature ul li h4 {
        height: 26px;
        font-weight: 700;
        font-size: 18px;
        color: #181818;
        line-height: 26px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-bottom: 0px;
        position: absolute;
        top: 30%;
        left: 40%;
    }

    main .feature ul li .special {
        margin-top: 65px;
    }

    main .feature ul li p {
        height: 40px;
        font-weight: 400;
        font-size: 14px;
        color: #4B5B76;
        line-height: 20px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 40px;
        position: absolute;
        top: 40%;
        width: 100%;
        /* left: 27%; */
    }

    main .dh {
        width: 100%;
        height: 64px;
        background: #FFFFFF;
        box-shadow: 0px 4px 10px 0px rgba(39, 111, 232, 0.05);
    }

    main .dh ul {
        width: 100%;
        height: auto;
        margin: auto;
    }

    main .dh ul li {
        width: 50%;
        text-align: center;
        font-weight: 400;
        font-size: 20px;
        color: #181818;
        line-height: 64px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        float: left;
    }

    main .dh ul li a {
        color: #181818;
    }

    main .dh ul .dh-on a {
        color: #0073FF;
        /* padding-bottom: 20px;
        border-bottom: 2px solid #0073FF; */
    }

    main .dh ul .dh-on samp {
        margin: auto;
        display: block;
        width: 40px;
        height: 3px;
        background: #0073FF;
    }

    main .dh ul li a:hover {
        color: #0073FF;
    }

}

@media (min-width: 992px) {
    main .content-gas {
        min-height: 1000px;
    }

    main .topbg {
        width: 100%;
        height: 530px;
        color: #181818;
        z-index: -99999;
        position: relative;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        background-position-x: 65%;
    }

    main .topbg .sxtitcen {
        /* width: 1200px; */
        height: 300px;
        margin: auto;
        padding-top: 155px;
        padding-left: 60px;
        position: relative;
    }

    main .topbg .sxtitcen p {
        /* width: 396px; */
        height: 32px;
        font-weight: 400;
        font-size: 22px;
        color: #FFFFFF;
        line-height: 32px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        z-index: -99999;
    }

    main .topbg .sxtitcen h2 {
        /* width: 512px; */
        height: 186px;
        font-weight: 700;
        font-size: 64px;
        color: #FFFFFF;
        line-height: 93px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        margin: 0px;
        z-index: -99999;
    }

    main .introduce {
        width: 100%;
        min-height: 1000px;
        background: #FFFFFF;
    }

    main .introduce div {
        /* width: 1200px; */
        min-height: 1000px;
        margin: auto;
        text-align: center;
    }

    main .introduce div h3 {
        width: 100%;
        min-height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 100px;
        margin-bottom: 0px;
        padding-bottom: 0px;
    }

    main .introduce div p {
        /* width: 100%; */
        min-height: 70px;
        font-weight: 400;
        font-size: 16px;
        color: #181818;
        line-height: 35px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        padding: 3%;
    }

    main .introduce div img {
        margin-top: 100px;
        width: 95%;
        height: auto;
        max-width: 800px;
        max-height: 800px;
        margin-bottom: 50px;
    }

    main .feature {
        width: 100%;
        min-height: 980px;
        background: #F5F7FA;
    }

    main .feature div {
        /* width: 1200px; */
        min-height: 1136px;
        margin: auto;
        text-align: center;
    }

    main .feature h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 0px;
        padding-top: 100px;
        margin-bottom: 80px;
    }

    main .feature ul {
        width: 75%;
        min-height: 600px;
        margin: auto;
    }

    main .feature ul li {
        width: 47%;
        height: 246px;
        border-radius: 4px 4px 4px 4px;
        background-repeat: no-repeat;
        background-position: center;
        background-color: #FFFFFF;
        background-position-y: 40px;
        background-size: 40px 40px;
        box-sizing: border-box;
        margin: auto;
        margin-bottom: 5%;
        margin-right: 3%;
        display: block;
        position: relative;
        float: left;
        max-width: 386px;
    }

    main .feature ul li h4 {
        height: 26px;
        font-weight: 700;
        font-size: 18px;
        color: #181818;
        line-height: 26px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-bottom: 0px;
        position: absolute;
        top: 30%;
        left: 40%;
    }

    main .feature ul li .special {
        margin-top: 65px;
    }

    main .feature ul li p {
        height: 40px;
        font-weight: 400;
        font-size: 14px;
        color: #4B5B76;
        line-height: 20px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 40px;
        position: absolute;
        top: 40%;
        width: 100%;
        /* left: 27%; */
    }

    main .dh {
        width: 100%;
        height: 64px;
        background: #FFFFFF;
        box-shadow: 0px 4px 10px 0px rgba(39, 111, 232, 0.05);
    }

    main .dh ul {
        width: 100%;
        height: auto;
        margin: auto;
    }

    main .dh ul li {
        width: 50%;
        text-align: center;
        font-weight: 400;
        font-size: 20px;
        color: #181818;
        line-height: 64px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        float: left;
    }

    main .dh ul li a {
        color: #181818;
    }

    main .dh ul .dh-on a {
        color: #0073FF;
    }

    main .dh ul .dh-on samp {
        margin: auto;
        display: block;
        width: 40px;
        height: 3px;
        background: #0073FF;
    }

    main .dh ul li a:hover {
        color: #0073FF;
    }

}

@media (min-width: 1200px) {
    main .content-gas {
        min-height: 3000px;
    }

    main .topbg {
        width: 100%;
        height: 760px;
        color: #181818;
        z-index: -99999;
        position: relative;
        background-repeat: no-repeat;
    }

    main .topbg .sxtitcen {
        width: 90%;
        height: 300px;
        margin: auto;
        padding-top: 230px;
        position: relative;
    }

    main .topbg .sxtitcen p {
        /* width: 396px; */
        height: 32px;
        font-weight: 400;
        font-size: 22px;
        color: #FFFFFF;
        line-height: 32px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        z-index: -99999;
    }

    main .topbg .sxtitcen h2 {
        /* width: 512px; */
        height: 186px;
        font-weight: 700;
        font-size: 64px;
        color: #FFFFFF;
        line-height: 93px;
        text-align: left;
        font-style: normal;
        text-transform: none;
        margin: 0px;
        z-index: -99999;
    }

    main .introduce {
        width: 100%;
        height: 1336px;
        background: #FFFFFF;
    }

    main .introduce div {
        width: 89%;
        height: 1336px;
        margin: auto;
        text-align: center;
        max-width: 1200px;
    }

    main .introduce div h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 100px;
        margin-bottom: 0px;
        padding-bottom: 80px;
    }

    main .introduce div p {
        width: 100%;
        height: 70px;
        font-weight: 400;
        font-size: 16px;
        color: #181818;
        line-height: 26px;
        text-align: left;
        font-style: normal;
        text-transform: none;
    }

    main .introduce div img {
        margin-top: 100px;
    }

    main .feature {
        width: 100%;
        min-height: 900px;
        background: #F5F7FA;
    }

    main .feature div {
        /* width: 1200px; */
        min-height: 900px;
        margin: auto;
        text-align: center;
    }

    main .feature h3 {
        width: 100%;
        height: 52px;
        font-weight: 700;
        font-size: 36px;
        color: #181818;
        line-height: 52px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 0px;
        padding-top: 100px;
        margin-bottom: 80px;
    }

    main .feature ul {
        width: 95%;
        min-height: 600px;
        margin: auto;
        max-width: 1200px;
    }

    main .feature ul li {
        width: 30%;
        height: 246px;
        border-radius: 4px 4px 4px 4px;
        background-repeat: no-repeat;
        background-position: center;
        background-color: #FFFFFF;
        background-position-y: 40px;
        background-size: 40px 40px;
        box-sizing: border-box;
        margin: auto;
        margin-bottom: 2%;
        margin-right: 15px;
        display: block;
        position: relative;
        float: left;
        max-width: 386px;
    }

    main .feature ul li h4 {
        height: 26px;
        font-weight: 700;
        font-size: 18px;
        color: #181818;
        line-height: 26px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-bottom: 0px;
        position: absolute;
        top: 30%;
        left: 40%;
    }

    main .feature ul li .special {
        margin-top: 65px;
    }

    main .feature ul li p {
        height: 40px;
        font-weight: 400;
        font-size: 14px;
        color: #4B5B76;
        line-height: 20px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        margin-top: 40px;
        position: absolute;
        top: 40%;
        width: 100%;
        /* left: 27%; */
    }

    main .dh {
        width: 100%;
        height: 64px;
        background: #FFFFFF;
        box-shadow: 0px 4px 10px 0px rgba(39, 111, 232, 0.05);
    }

    main .dh ul {
        width: 1200px;
        height: auto;
        margin: auto;
    }

    main .dh ul li {
        width: 600px;
        text-align: center;
        font-weight: 400;
        font-size: 20px;
        color: #181818;
        line-height: 64px;
        text-align: center;
        font-style: normal;
        text-transform: none;
        float: left;
    }

    main .dh ul li a {
        color: #181818;
    }

    main .dh ul .dh-on a {
        color: #0073FF;
        /* padding-bottom: 20px;
        border-bottom: 2px solid #0073FF; */
    }

    main .dh ul .dh-on samp {
        margin: auto;
        display: block;
        width: 40px;
        height: 3px;
        background: #0073FF;
    }

    main .dh ul li a:hover {
        color: #0073FF;
    }

}