message: Remove unnecessary buttons. Add full-screen button on viewer side.
diff: <div id="demo-container">
  <img src="landing-page/assets/imodel_viewer.png" class="example-view-demonstrator">
  <div class="overlay">
  -
  <script>
  function replaceViewer(e) {
  - document.getElementById("demo-container").innerHTML = "<a id='viewiModelBtn' class='btn btn-outline-secondary mb-2' href='./learning/public-viewer-demonstrator' role='button' target='_blank'>Open iModel.js Viewer Full Screen Example <i class='fa fa-external-link'></i> </a> <iframe src='./learning/public-viewer-demonstrator' class='iframe-viewer'></iframe>";
  + document.getElementById("demo-container").innerHTML = "<iframe src='./learning/public-viewer-demonstrator' class='iframe-viewer'></iframe>";
  e.preventDefault();
  }
  </script>
  <a id="viewiModelBtn" class="btn btn-outline-secondary mb-2" href="javascript:;" role="button" target="_blank"
  - onclick="replaceViewer(event)">Open iModel.js Viewer Example <i class="fa fa-external-link"></i> </a>
  - <a id='viewiModelBtn' class='btn btn-outline-secondary mb-2' href='./learning/public-viewer-demonstrator' role='button'
  - target='_blank'> Open iModel.js Viewer Full Screen Example <i class='fa fa-external-link'></i> </a>
  + onclick="replaceViewer(event)">Open iModel.js Viewer Example</a>
  +
  </div>
  </div>
  \ No newline at end of file
  