JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li></li>
<li></li>
<li></li>
</ul>

<hr />

<ul>
<li></li>
</ul>

CSS

li:first-child {
   border-top-left-radius: 5px;
   border-top-right-radius: 5px;
}

li:last-child {
   border-bottom-left-radius: 5px;
   border-bottom-right-radius: 5px;
}

li {
    background: rgb(180, 180, 180);
    padding: 10px;
    margin: 5px;
}