title: Vertical Menu with Show and hide by Arrow image
body: <p>I am newbie to web so, now am trying to create a menu with Arrow mark image to show/hide by clicking of image in vertical menu. Now I tried like below to click of menu it working but I have to show as like image :                                                               <img src="https://i.stack.imgur.com/0f0px.jpg" alt="enter image description here"> </p>
  
  <pre><code>  A
      --a
      --C
      ...D
    B
      --f
      --g
      ..i
  </code></pre>