JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Rainbow Text</h1>

CSS

h1 {
  font-size: 72px;
  background-image: -webkit-gradient(
    linear,
    left top,
    right top,
    color-stop(0.03, rgb(250,3,3)),
    color-stop(0.52, rgb(240,255,127)),
    color-stop(0.76, rgb(42,24,173))
);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}