html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    display: flex; /* enable flex layout */
    flex-direction: column; /* stack content vertically */
    align-items: center; /* center horizontally */
}

.page {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto; /* center block */
}