:root { color-scheme: light dark; font-family: "Segoe UI", "Microsoft YaHei", sans-serif; background: #fff; color: #191919; }
* { box-sizing: border-box; letter-spacing: 0; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 24px 12px; }
main { width: 100%; max-width: 360px; text-align: center; }
img { object-fit: contain; }
h1 { font-size: 22px; font-weight: 600; margin: 16px 0 8px; }
p { font-size: 14px; color: #606060; min-height: 42px; line-height: 1.6; margin: 0 0 20px; }
#challenge { min-height: 70px; display: flex; justify-content: center; }
button { font: inherit; padding: 8px 20px; border: 1px solid #b8b8b8; background: transparent; color: inherit; border-radius: 4px; cursor: pointer; margin-top: 20px; }
button:focus-visible { outline: 2px solid #167c80; outline-offset: 3px; }
@media (prefers-color-scheme: dark) { :root { background: #000; color: #fff; } p { color: #c3c3c3; } }