animate.css/source/back_exits/backOutDown.css

@keyframes backOutDown {
  0% {
    transform: scale(1);
    opacity: 1;
  }

  20% {
    transform: translateY(0px) scale(0.7);
    opacity: 0.7;
  }

  100% {
    transform: translateY(700px) scale(0.7);
    opacity: 0.7;
  }
}

.backOutDown {
  animation-name: backOutDown;
}