html {
    font-size: 100%;
}
body {
    margin: 0 auto;
    padding: 0;
    max-width: 720px;
    font-family: system-ui, sans-serif;
    font-weight: normal;
}
main {
    margin: 0 1rem;
}
header {
    padding: 0.5rem 1rem;
}