title: Line below and to the right of a button
body: <p><a href="https://i.stack.imgur.com/cluf5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cluf5.png" alt="enter image description here"></a></p>
  
  <p>You can see that the buttons have one darkish line at the bottom and to the right. How can I achieve this effect? Right now all I have is </p>
  
  <pre><code>#button {
  background-color:blue;
  }
  </code></pre>