"https://drafts.csswg.org/css2/#viewport">viewport</a>.
              </li>
              <li>|tba|'s height should be the same as the height of the
              regions in |ovls|.
              </li>
            </ol>
          </li>
          <li>Make {{Window/window}}.[[\TitleBarArea]] equal to |tba|.
          </li>
          <li>Update the [=title bar area env variables=] with information from
          {{Window/window}}.[[\TitleBarArea]].
          </li>
        </ol>
      </section>
    </section>
