:root { color-scheme: light dark; }
body { margin: 0; background: #f2f2f7; color: #202124; font: 16px/1.7 -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif; }
main { max-width: 420px; margin: 15vh auto; padding: 24px; text-align: center; }
main > img { border-radius: 16px; }
h1 { font-size: 28px; }
a { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 0 18px; color: #0066d6; text-underline-offset: 4px; }
a:focus-visible { outline: 3px solid currentColor; outline-offset: 4px; }
@media (prefers-color-scheme: dark) {
  body { background: #000; color: #f5f5f7; }
  a { color: #78b5ff; }
}