@media screen and (max-width: 720px) {
    #nav {
        left: 10px;
        top: 10px;
    }

    #nav .logo {
        width: 100px;
        height: 30px;
    }

    #nav span {
        font-size: 16px;
        height: 30px;
        line-height: 30px;
        margin-left: 10px;
    }

    .box h1 {
        font-size: 26px;
    }

    .box h4 {
        font-size: 18px;
    }

    .box .font-left {
        position: absolute;
        z-index: 1;
        top: 50px;
        margin-left: 6%;
    }

    .box .font-right {
        position: absolute;
        z-index: 1;
        top: 60px;
        margin-left: 55%;
        margin-right: 6%;
    }

    .box .font-center {
        top: 80px;
    }

    .footer {
        background-color: #111111;
        height: 150px;
        width: 100%;
        position: relative;
        float: left;
        color: white;
        text-align: center;
        font-size: 14px;
    }

    .footer p{
        margin-left: 10px;
        margin-right: 10px;
        margin-top: 5px;
    }

    .footer a {
        text-decoration: none;
        color: white;
    }

    .font-white2 {
        font-size: 18px;
        color: white;
        line-height: 1.8;
        margin-top: 15px;
    }

    .font-white5 {
        font-size: 16px;
        color: white;
        line-height: 1.2;
    }
    .about-frame {
        position: absolute;
        z-index: 1;
        top: 50px;
        background-color: rgba(0, 0, 0, 0.6);
        height: 330px;
        width: 46%;
    }

    .about-frame h3 {
        font-size: 36px;
        color: #24EDBA;
        margin-left: 50px;
    }

    .box .about-frame-left {
        margin-left: 3%;
    }

    .about-frame p {
        font-size: 18px;
        color: white;
        margin-left: 50px;
    }

    .box .about-frame-right {
        right: 2%;
    }

    .about-font-right {
        top: 10px;
        margin-left: 54%;
        margin-right: 6%;
    }

    .about-font-left {
        position: absolute;
        z-index: 1;
        top: 10px;
        margin-left: 6%;
    }

    .btn-send-email {
        height: auto;
        width: auto;
        color: #111111;
        font-size: 16px;
        padding: 12px 20px;
        margin-top: 20px;
        float: left;
        background-color: #24EDBA;
        border-radius: 5px;
        text-decoration: none;
        margin-left: 50px;
    }


    .app-qrcode{
        width: 100px;
        height: 100px;
    }
}