.logindiv{
    position: fixed;top: 50%;left: 50%;
    transform: translate(-50%, -50%);width: 100%;min-width: 320px;max-width: 420px;
    margin:auto;padding: 15px;text-align: center
}

.separator {
    border-top: 1px solid #D8D8D8;
    margin-top: 10px;
    padding-top: 10px;
}