JSFiddle - React, Tailwind, and code Playground

HTML

<div id="id2">
    <span>Demo</span>
</div>

CSS

#id2 .mycolor
  {
   color:white;                    
   background-color:red;
  }

  #id3:active
  {
   color:red;                    
   background-color:white;
  }

JavaScript

$('#id2').find('span').addClass('mycolor');