html, body {
    height: 100%;
}
body {
    display: flex;
    align-items: center;
    justify-content: center;
}
#form-contact {
    width: 100%;
    max-width: 640px;
    padding: 16px;
}
h3 {
    margin-bottom: 4px;
    font-weight: normal;
    font-size: 16px;
}
li {
    margin-bottom: 16px;
}
#btn-send {
    width: 120px;
    height: 40px;
}