* { box-sizing: border-box; }
html, body {
  margin: 0; height: 100%; overflow: hidden;
  background: #000; color: #fff;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  touch-action: none; user-select: none; -webkit-user-select: none;
}
#stage { position: fixed; inset: 0; overflow: hidden; }
#stage img, #stage canvas {
  position: absolute; left: 0; top: 0; max-width: none;
  transform-origin: 0 0; pointer-events: none;
  opacity: 0; transition: opacity .2s ease;
  will-change: transform, opacity;
}
#stage img.show, #stage canvas.show { opacity: 1; }
#status {
  position: fixed; left: 50%; top: 50%; transform: translate(-50%, -50%);
  padding: 14px 22px; border-radius: 12px;
  background: rgba(0,0,0,.65); font-size: 18px; text-align: center;
  pointer-events: none; max-width: calc(100vw - 32px);
}
#status[hidden] { display: none; }
#back {
  position: fixed; left: 12px; top: 12px; z-index: 20;
  padding: 6px 12px; border-radius: 8px;
  background: rgba(0,0,0,.55); color: #fff; text-decoration: none; font-size: 14px;
}