body {
    margin: 0;
    background: #161616;
    color: #f2f2f2;
    font: 18px/1.5 sans-serif;
}
main {
    max-width: 36rem;
    margin: 4rem auto;
    padding: 0 1.25rem;
}
.mark {
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-size: 0.75rem;
    color: #9a9a9a;
}
h1 { font-size: 2rem; font-weight: 600; }