rainbow-text.css

.rainbow-text {                                                                                                                                                                           
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-image: -webkit-gradient(linear,  left top,  left bottom, 
        color-stop(0.00, red), 
        color-stop(16%, orange),
        color-stop(32%, yellow),
        color-stop(48%, green),
        color-stop(60%, blue),
        color-stop(76%, indigo),
        color-stop(1.00, violet));
  }

cool