title: padding-left is working but padding-right is not
body: <p>I have a scrolling timeline (<a href="https://jsfiddle.net/abyk4gcj/4/" rel="nofollow">demo</a>) and I've encountered an issue where <code>padding-left</code> is working to hide the timeline branch images on the left side of the timeline before it's scrolled over, but <code>padding-right</code> is not working to hide the branch images on the right side.</p>
  
  <p>The method I'm attempting to use is that the branch image is inside a container <code>.event_line</code> which has <code>overflow: hidden</code> and the image has <code>padding-left</code> set to 100% until the section is scrolled to at which point <code>padding-left</code> animates down to 0%, revealing the image. This method works on the left side of the timeline, but not on the right.</p>
  
  <p>What do I need to change in order for <code>padding-right</code> to hide the branch images on the right side of the timeline?</p>