JSFiddle - React, Tailwind, and code Playground

HTML

<div id="leftNav">
        <ul>
           <li><a href="#">A <span class="subTitle">Subtitle</span></a></li>
           <li><a href="#">B <span>Subtitle</span></a></li>
           <li><a href="#">C <span class="subTitle">Subtitle</span></a></li>
           <li><a href="#">D <span>Subtitle</span></a></li>
           <li><a href="#">E <span class="subTitle">Subtitle</span></a></li>
        </ul>
</div>

CSS

#leftNav ul li { position: relative; }
#leftNav ul li a span.subTitle
{
   bottom:          4px;
   display:         block;
   font-size:       12px;
   left:            10px;
   position:        absolute;
    color: red;
}