t scrollable area. -->
<div class="scroller" style="display: flex; flex-direction: row-reverse;">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" data-offset-x="-100" data-offset-y="0" data-expected-width="200" data-expected-height="200"></div>
</div>

<!-- Use RTL to trigger right scrollable area. -->
<div class="scroller" style="direction: rtl;">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" data-offset-x="-100" data-offset-y="0" data-expected-wi