body {
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: 100vh;
    padding-inline: 1ch;
    margin: 0;
}

.hidden {
    display: none;
}

body,
form,
input {
    font-size: 18pt;
    font-family: Arial;
}

form {
    margin: 0;
}

h1,
#formResult {
    margin-bottom: 0;
}