title: Webkit button: background color overflows round corners
body: <p>I'm trying to make a rounded button using <code>-webkit-border-radius</code></p>
  
  <p>This gives me this button (in Safari):</p>
  
  <p><img src="https://i.stack.imgur.com/12yqy.png" width="134" height="101" alt="round corner with background color" /></p>
  
  <p>You can see that the background color overflows in the rounding. I tried changing border size and radius, but it doesn't help. Is this a rendering bug with Safari or something?</p>