.flash-btn {
  opacity: 1;

  &:hover,
  &.animated {
    animation-name: flash;
    animation-duration: 0.6s;
    animation-timing-function: ease-in-out;
    animation-direction: alternate;
    animation-iteration-count: infinite;
    animation-play-state: running;
  }
}

@keyframes flash {
  0% {
    opacity: 1;
  }

  100% {
    opacity: 0;
  }
}