JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
  <li>Teste1</li>
  <li>Teste2</li>
  <li>Teste3</li>
  <li>Teste4</li>
  <li>Teste5</li>
  <li>Teste6</li>
  <li>Teste7</li>
  <li>Teste8</li>
  <li>Teste9</li>
</ul>

CSS

li:nth-child(3n + 1){
    color: red;
}
li:nth-child(3n + 2){
    color: blue;
}
li:nth-child(3n){
    color: green;
}