title: when using zurb foundation orbit slider, how to center slides
body: <p>as shown in this screenshot:
  <img src="https://i.stack.imgur.com/c0beQ.png" alt="extra wide screen causes background to show through">
  on my 24" monitor the white background shows through my orbit slider.
  This is because my source image is narrower (in pixels) than the browser window's width.</p>
  
  <p>If I make my window narrower, the image scales down as one would expect, without any background showing through:
  <img src="https://i.stack.imgur.com/jSfhU.png" alt="no background when window is 1600px wide or narrower"></p>
  
  <p>What I would like to accomplish is to center the <code>&lt;li&gt;</code> elements that make up the slides so that when the image is narrower it won't have dumb looking white stripe on one side.
  <img src="https://i.stack.imgur.com/S6V9i.png" alt="browser inspector showing ul/li elements"></p>