@keyframes swing {
  20% {
    transform: rotate(15deg);
  }

  40% {
    transform: rotate(-10deg);
  }

  60% {
    transform: rotate(5deg);
  }

  80% {
    transform: rotate(-5deg);
  }

  100% {
    transform: rotate(0deg);
  }
}

.swing {
  transform-origin: top center;
  animation-name: swing;
}