font-awesome-animation/scss/vertical.scss

$faa-vertical-speed: 2s;
@keyframes vertical {
  0%, 8%, 16% {
    transform: translate(0,-3px);
  }
  4%, 12%, 20% {
    transform: translate(0,3px);
  }
  22%, 100% {
    transform: translate(0,0);
  }
}
.faa-vertical.animated,
.faa-vertical.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-vertical {
  animation: vertical $faa-vertical-speed ease infinite;
}
.faa-vertical.animated.faa-fast,
.faa-vertical.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-vertical.faa-fast {
  animation: vertical ($faa-vertical-speed * $faa-speed-coeff-fast) ease infinite;
}
.faa-vertical.animated.faa-slow,
.faa-vertical.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-vertical.faa-slow {
  animation: vertical ($faa-vertical-speed * $faa-speed-coeff-slow) ease infinite;
}