.animated {
  -webkit-animation: filter-animation 20s infinite;
  animation: filter-animation 20s infinite;
}

@-webkit-keyframes filter-animation {
  0% {
    -webkit-filter: hue-rotate(0deg);
  }

  50% {
    -webkit-filter: hue-rotate(360deg);
  }

  100% {
    -webkit-filter: hue-rotate(0deg);
  }
}

@keyframes filter-animation {
  0% {
    filter: hue-rotate(0deg);
  }

  50% {
    filter: hue-rotate(360deg);
  }

  100% {
    filter: hue-rotate(0deg);
  }
}