JSFiddle - React, Tailwind, and code Playground

HTML

<div class="commentList">
    <article class="comment" id="com21"><span class="test">19</span></article>

    <article class="comment" id="com20"><span class="test">19</span></article>

    <article class="comment" id="com19">
      <span class="test">19</span>
    </article>
    
    <div class="something"> hello </div>
</div>

CSS

.comment .test{
    width:470px;
    border-bottom:1px dotted red;
    margin-bottom:10px;
}

.comment:last-of-type .test {
    border-bottom:none;
    margin-bottom:0;
}