JSFiddle - React, Tailwind, and code Playground

HTML

<div class="contentBox"> 
      <p>I have some content that is good to read</p>
   </div>

CSS

span{background-color:red;}

JavaScript

$(function(){
    $('.contentBox p').each(function(){
      var text = $(this).text();
      var first = text.substring(0,26);
      var second = text.substring(26,text.length);
      $(this).html(first + '<span>' + second + '</span>');  
    });
});