CSS animation to sweep background-colors

animation.css

.whatever {
  animation-name: color-transition;
  animation-duration: 25s;
  animation-direction: alternate;
  animation-iteration-count: infinite;
  animation-timing-function: linear;
}

@keyframes color-transition {
  0% {
    background-color: #4c6085;
    border-color: #4c6085;
  }
  33% {
    background-color: #80d39b;
    border-color: #80d39b;
  }
  66% {
    background-color: #be3e82;
    border-color: #be3e82;
  }
  100% {
    background-color: #4c6085;
    border-color: #4c6085;
  }
}