title: How to make a input submit button with flat look?
body: <p>Here I have a submit button:</p>
  
  <pre><code>&lt;input type="submit" value="submit" /&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/FpOqg.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FpOqg.png" alt="The white button on the right side"></a></p>
  
  <p>And I want to add some additional styles to make it a flat look:</p>
  
  <pre><code>input {
      border: 0;
      background: none;
      -webkit-appearance: none;
  }
  </code></pre>
  
  <p>This is how it looks afterwards: 
  <a href="https://i.stack.imgur.com/KJXpu.png" rel="noreferrer"><img src="https://i.stack.imgur.com/KJXpu.png" alt="The button has the same background-color as its background"></a></p>
  
  <p>However, if you look carefully, there is still some border on the top of the submit button......
  Is there some way to remove the sunken or raised surface and make it a plain flat look?</p>