JSFiddle - React, Tailwind, and code Playground

HTML

<a id="test1" href="#a">test1</a>
<a id="test2" href="#b">test2</a>
<input type="button" id="StyleAnchors" value="Style Visited Anchors" />

JavaScript

$(document).ready(function()
{
  $("#StyleAnchors").click(function()
    {
      //works
      $("a").css("background-color", 'yellow');
      //doesn't works
      $("a:visited").css("background-color", 'red');
      
      //works
      document.styleSheets[0].addRule('a:visited', 'color: green');
      //document.styleSheets[0].insertRule('a:visited{background-color: #00f;}');
    });
});