JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>   
    <li>
      <div>.....</div>
    </li>
</ul>

CSS

li > div {
  margin-right: 10px;
}

li:nth-child(3n) > div {
  margin-right: 0px;
}