.container {
  display: inline-flex;
  overflow: hidden;
}

.letter {
  display: inline-block;
  opacity: 0;
  animation-fill-mode: forwards;
  animation-timing-function: cubic-bezier(0.19, 1, 0.22, 1);
}

.down {
  animation-name: fall-down;
}

.up {
  animation-name: fall-up;
}

.loop {
  animation-iteration-count: infinite;
}

@keyframes fall-down {
  0% {
    opacity: 0;
    transform: translateY(-100%) rotate(-10deg);
  }
  20% {
    opacity: 1;
  }
  80% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: translateY(100%) rotate(10deg);
  }
}

@keyframes fall-up {
  0% {
    opacity: 0;
    transform: translateY(100%) rotate(10deg);
  }
  20% {
    opacity: 1;
  }
  80% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: translateY(-100%) rotate(-10deg);
  }
}