@media screen and (max-width: 640px) {
    .container {
        width: 320px !important;
        margin: 0 auto;
        /*padding: 0 19px;*/
        position: relative;
        /* height: 2000px;
 background-color: rgba(255, 255, 255, 0.7);*/
    }

    .header .container {
        max-width: 320px !important;
    }

    .header .logo {
        margin: 24px auto 0;
        display: block;
    }

    .img-fluid {
        max-width: 100%;
        height: auto;
        margin-bottom: 30px !important;
    }

    .content {
        width: auto;
    }

    .title {
        font-size: 23px;
        /*text-align: center;*/
    }

    .column-container {
        max-width: 320px;
        /*margin: 350px auto 0 auto;*/
    }

    #sec1 {
        height: 69px;
        position: relative;
        position: sticky;
        background-color: rgba(26,26,26,0.8);
    }

        #sec1 .logo1 {
            width: 143px;
            height: 22px;
            position: absolute;
            left: 0px;
            top: 25px;
            display: inline-block;
            background: url(../images/logo-1_640.png) center;
        }

        #sec1 .logo2 {
            width: 143px;
            height: 27px;
            position: absolute;
            right: 0px;
            top: 25px;
            display: inline-block;
            background: url(../images/logo-2_640.png) center;
        }


    #sec2 {
        background: url('../images/NV_2042_w640_01.jpg') center top no-repeat;
        position: relative;
        padding-top: 400px;
    }

        #sec2 .column-container {
            max-width: 320px;
            padding-top: 60px;
            left: auto;
            margin-left: auto;
            margin: 0 auto;
        }

        #sec2 .link-btn {
            font-size: 14px;
        }

        #sec2 .titleb {
            font-size: 40px;
        }

        #sec2 .container {
            max-width: 320px !important;
        }

    .wid-70 {
        width: 100%;
    }

    #sec3 {
        height: auto;
    }

        #sec3 .container {
            top: -20px;
            margin: 1rem auto;
        }

    #sec4 {
        height: auto;
    }

        #sec4 .imgrwd {
            padding-top: 0;
        }

    #sec2 .content {
        padding-right: 0px;
        padding-left: 0px;
        margin: 0px auto;
    }

    #sec3 .title, #sec4 .title, #sec5 .title, #sec6 .title {
        font-weight: normal;
        font-size: 22px;
        line-height: 1;
    }

    #sec7 .title, #sec8 .title {
        font-weight: normal;
        font-size: 30px;
        line-height: 1;
    }

    .txtgreen {
        line-height: 1;
    }

    .hr {
        max-width: 320px;
    }

    #productbox .title {
        font-size: 24px;
    }

    #productbox .top {
        margin: 0 auto 20px;
    }

    #productbox .txt {
        width: 320px;
    }

    .model-name {
        font-size: 22px;
        line-height: 1.2;
    }

    .fr #sec3 {
        height: 750px;
    }

    .p-t-120 {
        padding-top: 90px;
    }

    #sec3 .content {
    }

    .hr {
        margin: 30px auto;
    }

    .btnvideo {
        color: #fff;
        background-color: #77b900;
        padding: 7px 12px;
        font-size: 15px;
        text-decoration: none;
        /* margin-top: 15px; */
        display: block;
        text-transform: uppercase;
        cursor: pointer;
        transition-duration: .5s;
        width: 100px;
        /* text-align: center; */
        margin: 30px auto;
    }

    #sec4 {
        text-align: center;
    }

    .item-model:hover rect {
        stroke-width: 10;
        stroke-dasharray: 160, 750;
    }


    #productbox .center {
        padding: 0;
        width: 320px;
        margin: 0 auto;
    }

    .row {
        display: block;
        text-align: left;
        font-size: 0;
    }

    .column {
        display: inline-block;
        vertical-align: top;
        font-size: 12px;
    }

    .alcenter {
        text-align: center;
    }

    .row-3 .column {
        width: 100%;
    }

        .row-3 .column .large {
            display: none;
        }

        .row-3 .column .small {
            display: inline-flex;
        }

    .row-3 {
        padding-top: 0;
    }

    .list {
        list-style: none;
        margin: 0;
        padding: 0;
    }

    .list-model {
        width: 278px;
        margin: 0 auto 60px;
    }

        .list-model li {
            margin-bottom: 7px;
        }

    .item-model {
        color: #fff;
        line-height: 1;
        text-align: center;
    }

        .item-model a {
            position: relative;
            padding: 9px 0;
            display: block;
            color: inherit;
            margin-top: 20px;
            text-decoration: none;
        }



        .item-model .model-spec {
            line-height: 1.25;
            margin: 0 22px;
        }



    span.color2 {
        font-size: 14px;
        color: #fff;
    }

    .text-imgtitle {
        font-size: 18px;
        line-height: 30px;
    }

    span.color-1 {
        font-size: 15px;
        /*font-weight: bolder;*/
    }

    #sec9 .titleb {
        padding: 70px 0 20px 0;
    }

    #sec10 {
    }

        #sec10 .content {
            padding: 480px 0 0 0;
        }

        #sec4 .content, #sec10 .content, #sec6 .content, #sec7 .content {
            width: 100%;
        }

    #sec6 .content {
        width: 100%;
        padding: 440px 0 0 0;
    }

    #sec7 {
    }

        #sec7 .content {
            width: 100%;
            padding: 440px 0 0 0;
        }

    .row-33 .column {
        width: 100%;
    }

        .row-33 .column .large {
            display: none;
        }

        .row-33 .column .small {
            display: inline-flex;
        }

    #footer .container {
        width: 320px;
        padding-top: 0;
        padding: 400px 0 50px 0;
    }

    #sec3 .content, #sec5 .content {
        width: 290px;
        height: 170px;
        margin: 0 auto;
    }

    .buy-list {
        /*display:inline;*/
    }

    .footer {
        background: url(../images/RTXStudio_w640_footer.jpg) center top no-repeat;
        background-color: #000;
    }
    #btn-box .text-w {
        font-size: 1.5em;
        
        margin: 0 auto;
        text-align: center;
    }
    /*nav*/
    .tab-content a.hlink-t {
   width:100% }
    .nav-tabs .nav-link {
        font-size: 1.2em !important;
      
    }
}