title: add popup on :after pseudo element with css
body: <p>I'm interesting is there are a way to add a small popup box on <code>:after</code> pseudo element when I hover it? Is it possible to do it without HTML at all? I tried to search the web for it, but it seems that I always need some kind of <code>&lt;span&gt;</code> or <code>&lt;div&gt;</code> elements in markup to display popup text. Although I want to do it with pure CSS. Is there are some tricks for that?</p>
  
  <pre><code>button::after {
    content: "i";
    color: blue;
  }
  
  button:hover::after {
    color: red;
    cursor: pointer;
    // add css to display popup
  }
  </code></pre>