body { margin: 0; font-family: system-ui, sans-serif; background: #f6f7f9; color: #222; }
main { max-width: 640px; margin: 64px auto; padding: 0 16px; }
h1 { font-size: 28px; }
footer { max-width: 640px; margin: 0 auto 32px; padding: 0 16px; color: #888; font-size: 14px; text-align: center; }