   </div></article>
</div>
      </main><div>
  <section class="sidebar">
    <!-- video on intro to testing (with playlist) -->
    <!-- <iframe
      src="https://www.youtube.com/embed/videoseries?si=7gmhXY5DVYJG7OdU&amp;list=PLofhE49PEwmwLR_4Noa0dFOSPmSpIg_l8"
      title="YouTube video player"
      frameborder="0"
      allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
      referrerpolicy="strict-origin-when-cross-origin"
      allowfullscreen
