html, body {
    height: 100%;
}
body {
    display: flex;
    align-items: center;
    justify-content: center;
}
#panel {
    width: 100%;
    max-width: 640px;
    padding: 16px;
}
h1 {
    font-weight: normal;
    font-size: 32px;
    margin-bottom: 16px;
}
#panel p {
    font-size: 18px;
    line-height: 180%;
}