@media screen and (min-width: 600px) {
    .auth-wrapper .auth-box {
        background: #fff;
        padding: 20px;
        box-shadow: 1px 0 20px rgba(0,0,0,.08);
        max-width: 400px !important;
        margin: 10% 0;
    }
}

@media screen and (max-width: 600px) {
    .auth-wrapper .auth-box {
        background: #fff;
        padding: 20px;
        box-shadow: 1px 0 20px rgba(0,0,0,.08);
        max-width: 100% !important;
        width: 100% !important;
        margin: 10% 0;
    }
}