swing.css

@keyframes swing {
  20% {
    transform: rotate3d(0, 0, 1, 15deg);
  }

  40% {
    transform: rotate3d(0, 0, 1, -10deg);
  }

  60% {
    transform: rotate3d(0, 0, 1, 5deg);
  }

  80% {
    transform: rotate3d(0, 0, 1, -5deg);
  }

  to {
    transform: rotate3d(0, 0, 1, 0deg);
  }
}

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