@media screen and (max-width:39.99em) {
    div#authen {
        width: calc(100% - 8px);
        max-width:calc(100vw - 8px);
        top: 2px;
        left: 1px;
        margin: 0 4px;
    }
}

@media screen and (min-width : 40em) and (max-width:62em) {
    div#authen {
        width: 50%;
        top:20vh;
        margin-left:-25%;
    }
}