.rainbow {
    animation: colorRotate .5s linear 0s infinite;
  }

  @keyframes colorRotate {
    from {
      color: #6666ff;
    }
    10% {
      color: #0099ff;
    }
    50% {
      color: #00ff00;
    }
    75% {
      color: #ff3399;
    }
    100% {
      color: #6666ff;
    }
  }