JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="pt-br">
  <head>
    <meta charset="UTF-8"/>
    <meta name="viewport" content="width=device-width">
    <title>Menu com Background na lista</title>
    <style>
      nav {
        position: relative;
        top: 12px;
        width: 500px;
        margin: auto;
      }
      nav ul {
        position: absolute;
      }
      nav li {
         background-color: yellow;
         list-style: none;
         display: inline;
         padding: 15px;
         margin-left: 5px;
         text-transform: uppercase;
         border: 2px solid #CCC;
         text-shadow: 2px 1px 1px #D3D3D3;
      }
    </style>
  </head>
  <body>
    <nav>
      <ul>
        <li>Home</li>
        <li>Serviços</li>
        <li>Sobre</li>
        <li>Contato</li>
      </ul>
    </nav>
  </body>
</html>