Default left and right pane height will share the total width of page and the divider will be placed accordingly.

Example Code

<div class="two-pane-vertical">
  <div class="pane-left">
    <div class="pane">
      <h3 class="title">Two pane - Vertical</h3>
      <section>
        <!--Content Goes Here -->
      </section>
    </div>
  </div>
  <div class="divider twopanedivider-vertical"></div>
  <div class="pane-right">
    <div class="pane">
      <div class="pane-header-bg">
        <h3 class="title">Right Panel: Vertical</h3>
      </div>
      <div class="bottom-content-panel">
        <!--Content Goes Here -->
      </div>
    </div>
  </div>
</div>