html,
body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: #6ec1f5;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior: none;
}

#game {
  width: 100%;
  height: 100%;
}

#rotate {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 10;
  align-items: center;
  justify-content: center;
  background: #6ec1f5;
}

/* Phones held upright: the game is wide, so ask to turn the phone. */
@media (orientation: portrait) and (max-width: 600px) {
  #rotate {
    display: flex;
  }
}

/* The phone icon turns sideways, again and again. */
#rotate .phone {
  transform-origin: 60px 60px;
  animation: turn 2.4s ease-in-out infinite;
}

@keyframes turn {
  0%,
  25% {
    transform: rotate(0deg);
  }
  55%,
  90% {
    transform: rotate(-90deg);
  }
  100% {
    transform: rotate(0deg);
  }
}