JSFiddle - React, Tailwind, and code Playground

HTML

<div id="testMenu">
  <ul>
    <li>첫번째</li>
    <li>두번째</li>
    <li>세번쨰</li>
    <li>네번째</li>
  </ul>
</div>

CSS

#testMenu {
  border: 1px solid black;
}
#testMenu > ul{
  width: 800px;
  height: 30px; 
}
#testMenu > ul li {
  display:inline-block; 
  margin-left: 40px; 
  line-height: 30px;
}