font-awesome-animation/scss/spin.scss

$faa-spin-speed: 1.5s;
@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(359deg);
  }
}
@keyframes spin-reverse {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(-359deg);
  }
}
.faa-spin.animated,
.faa-spin.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-spin {
  animation: spin $faa-spin-speed linear infinite;
}
.faa-spin.animated.faa-fast,
.faa-spin.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-spin.faa-fast {
  animation: spin ($faa-spin-speed * $faa-speed-coeff-fast) linear infinite;
}
.faa-spin.animated.faa-slow,
.faa-spin.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-spin.faa-slow {
  animation: spin ($faa-spin-speed * $faa-speed-coeff-slow) linear infinite;
}
.faa-spin.faa-reverse.animated,
.faa-spin.faa-reverse.animated-hover:hover,
.faa-parent.animated-hover:hover > .faa-spin.faa-reverse {
  animation: spin-reverse $faa-spin-speed linear infinite;
}
.faa-spin.faa-reverse.animated.faa-fast,
.faa-spin.faa-reverse.animated-hover.faa-fast:hover,
.faa-parent.animated-hover:hover > .faa-spin.faa-reverse.faa-fast {
  animation: spin-reverse ($faa-spin-speed * $faa-speed-coeff-fast) linear infinite;
}
.faa-spin.faa-reverse.animated.faa-slow,
.faa-spin.faa-reverse.animated-hover.faa-slow:hover,
.faa-parent.animated-hover:hover > .faa-spin.faa-reverse.faa-slow {
  animation: spin-reverse ($faa-spin-speed * $faa-speed-coeff-slow) linear infinite;
}