font-awesome-animation/scss/falling.scss

$faa-falling-speed: 2s;
@keyframes falling {
  0% {
    transform:translateY(-50%);
    opacity:0;
  }
  50% {
    transform:translateY(0%);
    opacity:1;
  }
  100% {
    transform:translateY(50%);
    opacity:0;
  }
}
@keyframes falling-reverse {
  0% {
    transform:translateY(50%);
    opacity:0;
  }
  50% {
    transform:translateY(0%);
    opacity:1;
  }
  100% {
    transform:translateY(-50%);
    opacity:0;
  }
}
.faa-falling.animated,
.faa-falling.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-falling {
  animation: falling $faa-falling-speed linear infinite;
}
.faa-falling.animated.faa-fast,
.faa-falling.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-falling.faa-fast {
  animation: falling ($faa-falling-speed * $faa-speed-coeff-fast) linear infinite;
}
.faa-falling.animated.faa-slow,
.faa-falling.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-falling.faa-slow {
  animation: falling ($faa-falling-speed * $faa-speed-coeff-slow) linear infinite;
}
.faa-falling.faa-reverse.animated,
.faa-falling.faa-reverse.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-falling.faa-reverse,
.faa-rising.animated,
.faa-rising.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-rising {
  animation: falling-reverse $faa-falling-speed linear infinite;
}
.faa-falling.faa-reverse.animated.faa-fast,
.faa-falling.faa-reverse.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-falling.faa-reverse.faa-fast,
.faa-rising.animated.faa-fast,
.faa-rising.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-rising.faa-fast {
  animation: falling-reverse ($faa-falling-speed * $faa-speed-coeff-fast) linear infinite;
}
.faa-falling.faa-reverse.animated.faa-slow,
.faa-falling.faa-reverse.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-falling.faa-reverse.faa-slow,
.faa-rising.animated.faa-slow,
.faa-rising.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-rising.faa-slow {
  animation: falling-reverse ($faa-falling-speed * $faa-speed-coeff-slow) linear infinite;
}