code: function() {
      var self = this;
  
      // Calculate the scale of our window from "full" size.
      var scale = window.innerWidth / 3600;
  
      // Resize and reposition the sprite overlays.
      var keys = Object.keys(self._spriteMap);
      for (var i=0; i<keys.length; i++) {
        var sprite = window[keys[i]];
        sprite.style.width = Math.round(self._width[i] * scale) + 'px';
        if (self._left[i]) {
          sprite.style.left = Math.round(self._left[i] * scale) + 'px';
        }
      }
    }
docs: Called on window resize to correctly psotion and size the click overlays.