animate.css/source/rotating_exits/rotateOutDownLeft.css

@keyframes rotateOutDownLeft {
  0% {
    transform-origin: left bottom;
    transform: rotate(0);
    opacity: 1;
  }

  100% {
    transform-origin: left bottom;
    transform: rotate(90deg);
    opacity: 0;
  }
}

.rotateOutDownLeft {
  animation-name: rotateOutDownLeft;
}