title: CSS "sunken"/"inset" letter effect without using image
body: <p>How is the "sunken" or "inset" effect applied to these letters in this menu?  I looked (briefly) with Firebug but can't find how they're doing it.  Works in FF, not in IE.</p>
  
  <p><img src="https://i.stack.imgur.com/P4SSj.jpg" alt="alt text"></p>
  
  <p>See <a href="http://balsamiq.com/products/mockups/mybalsamiq" rel="nofollow noreferrer">http://balsamiq.com/products/mockups/mybalsamiq</a> for actual example.</p>