JSFiddle - React, Tailwind, and code Playground

HTML

<div class="comment-list"> </div>
      
<div class="comment-list">
    foo<br/>foo<br>foo<br>foo<br>foo<br>foo<br>foo<br>foo<br>
    foo<br>foo<br>foo<br>foo<br>foo<br>foo<br>foo<br>foo<br>
</div>

CSS

.comment-list {
    margin: 20px 0;
    max-height: 100px;
    min-height: 100px;
    overflow-y: auto;
    width: 100%;
    background-color:#000;
}