* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { width: 100%; height: 100%; overflow: hidden; background: #1a1a2e; touch-action: none; user-select: none; }
#app { position: relative; width: 100%; height: 100%; }
canvas { display: block; width: 100%; height: 100%; }
#hud {
  position: absolute; top: 0; left: 0; right: 0;
  display: flex; justify-content: space-between;
  padding: 10px 16px;
  font: bold 15px sans-serif; color: #fff;
  pointer-events: none;
  background: linear-gradient(to bottom, rgba(0,0,0,0.5), transparent);
}
#overlay {
  position: absolute; inset: 0;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  background: rgba(0,0,0,0.7);
  z-index: 10;
}
#overlay.hidden { display: none; }
#overlay-title { font: bold 26px sans-serif; color: #ffd700; margin-bottom: 8px; }
#overlay-sub { font: 16px sans-serif; color: #ccc; margin-bottom: 20px; text-align: center; }
#btn-next {
  padding: 12px 40px; font: bold 20px sans-serif;
  background: #2d8a4e; color: #fff; border: none; border-radius: 10px;
  cursor: pointer;
}