body {
    display: flex;
    flex-direction: column;
    margin-left: auto;
    margin-right: auto;
    font-size: x-large;
}

header {
    text-align: center;
}

main {
    max-width: 800px;
    display: block;
    margin: 50px auto 50px auto;
}

#centering {
    text-align: center;
}

#centering img {
    display: block;
    margin: auto;
    max-width: 900px;
}