.loginBox {
}

.loginOuter {
    display: table;
    position: absolute;
    height: 100%;
    width: 100%;
}

.loginMiddle {
    display: table-cell;
    vertical-align: middle;
}

.loginInner {
    margin-left: auto;
    margin-right: auto;
    margin-top: -50px;
    width: 350px;
    /*whatever width you want*/
}

@media (max-width: 573px) {
    .login_bg {
        display: none !important;
    }
}