html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: #05070d;
  touch-action: none;
}

body {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

#game-shell {
  position: relative;
  width: min(100vw, 430px);
  height: 100vh;
}

#game-canvas {
  display: block;
  width: 100%;
  height: 100%;
  background: #05070d;
}

#debug-overlay {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 1000;
  min-width: 96px;
  padding: 6px 8px;
  border-radius: 4px;
  background: rgba(0, 0, 0, 0.58);
  color: #ffffff;
  font: 700 12px/1.35 Arial, "Microsoft YaHei", sans-serif;
  pointer-events: none;
  white-space: nowrap;
}

@media (max-width: 600px) {
  #game-shell {
    width: 100vw;
    height: 100vh;
  }
}