:root { color-scheme: light dark; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; font: 16px/1.6 -apple-system, "PingFang TC", sans-serif; background: #f6f1e7; color: #2a2a2a; }
.box { text-align: center; padding: 24px 16px; max-width: 360px; }
h1 { font-size: 20px; margin: 0 0 12px; }
button { min-height: 44px; padding: 0 24px; font-size: 16px; border: 0; border-radius: 8px; background: #06c755; color: #fff; }
button:focus-visible { outline: 3px solid #2a2a2a; outline-offset: 2px; }
.err { color: #b3261e; }
@media (prefers-color-scheme: dark) { body { background: #1c1b18; color: #eee; } }