.rainbow-text {
    background-image: repeating-linear-gradient(45deg, violet, indigo, blue, green, yellow, orange, red, violet);
    text-align: center;
    background-size: 800% 800%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: rainbow 10s ease infinite;
}
@keyframes rainbow { 
      0%{background-position:0% 50%}
      50%{background-position:100% 25%}
      100%{background-position:0% 50%}
}