animate.css/source/rotating_entrances/rotateInDownRight.css

@keyframes rotateInDownRight {
  0% {
    transform-origin: right bottom;
    transform: rotate3d(0, 0, 1, 45deg);
    opacity: 0;
  }

  100% {
    transform-origin: right bottom;
    transform: none;
    opacity: 1;
  }
}

.rotateInDownRight {
  animation-name: rotateInDownRight;
}