JSFiddle - React, Tailwind, and code Playground

HTML

<div class="nav-bar-wrapper">
       <nav id="nav-bar">
          <ul>
            <li><a class="nav-link" href="#">link1</a></li>
            <li><a class="nav-link" href="#">link2</a></li>
            <li><a class="nav-link" href="#">link3</a></li>
            <li><a class="nav-link" href="#">link4</a></li>
          </ul>
        </nav>
</div>

CSS

ul {
    display: flex;
    align-items: stretch;
    justify-content: space-between;
    width: 100%;
    background: #cacaca;
    margin: 0;
    padding: 0;

}
li {
    border: 3px solid;
    display: block;
    flex: 1 1 auto;
    list-style-type: none;
    background: #fafafa;
    text-align: center;
}