title: Why isn't CSS visibility working?
body: <p>I added a "spoiler" class in CSS to use for, well, spoilers. Text is normally invisible but appears when the mouse hovers over it to reveal the spoiler to whoever wants to read it.</p>
  
  <pre><code>.spoiler{
      visibility:hidden;
  
  }
  .spoiler:hover {
      visibility:visible;
  }
  </code></pre>
  
  <p>Should be simple, but for some reason this doesn't work. The text remains invisible even when I point the mouse on it. Any idea what could be causing this?</p>