html, body {
    height: 100%;
}

body {
    display: flex;
    padding-top: 40px;
    padding-bottom: 40px;
    align-items: center;
    text-align: center;
}

.signin-form {
    width: 100%;
    max-width: 430px;
    padding: 15px;
    margin: auto;
}

.signin-form input {
    margin: 20px 0px;
}