:root { --bg: #14141c; --fg: #e8e8f0; --muted: #8a8aa0; }
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; background: var(--bg); color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif; }
body { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 10px;
  overflow: hidden; touch-action: none; -webkit-user-select: none; user-select: none; }
#wrap { position: relative; }
#screen { display: block; image-rendering: pixelated; image-rendering: crisp-edges; background: #6ab4f8;
  box-shadow: 0 0 0 3px #000, 0 10px 40px rgba(0, 0, 0, 0.6); }
.help { margin: 0 16px; font-size: 13px; color: var(--muted); text-align: center; line-height: 1.6; }
.help b { color: var(--fg); }

/* 觸控按鈕：半透明，疊在畫面下方兩側 */
#touch { position: absolute; inset: auto 0 8px 0; display: flex; justify-content: space-between; padding: 0 10px; pointer-events: none; }
#touch[hidden] { display: none; }
#touch div { display: flex; gap: 6px; pointer-events: auto; }
#touch button { width: 50px; height: 50px; border-radius: 50%; border: 2px solid rgba(255, 255, 255, 0.55);
  background: rgba(0, 0, 0, 0.28); color: rgba(255, 255, 255, 0.9); font: bold 20px system-ui, sans-serif; touch-action: none; }
#touch button.on { background: rgba(255, 255, 255, 0.35); }
body.touch .help { display: none; }