body {
}
#LoginDiv, #SignupDiv {
    max-width: 400px;
    margin-top: 50px;
}

#SignupDiv {
    display: none;
}

    #LoginDiv .card, #SignupDiv .card {
        padding: 5px;
    }

body > .container {
    max-width: 400px;
    padding: 0;
}

#LoginDiv input[type=submit] {
    margin-top: 10px;
}