src/panel.html
<!DOCTYPE html>
<html>
<body>
<link rel="stylesheet" type="text/css" href="style.css" />
<div id="app">
<div class="container">
<div class="panel left control-deck">
<div class="panel-list">
<div class="loading">Loading...</div>
</div>
</div>
<div class="panel content with-heading"></div></div>
</div>
</div>
<div id="notifier"></div>
<script src="browser-polyfill.min.js" charset="utf-8"></script>
<script src="messaging.js" charset="utf-8"></script>
<script src="panel.js" charset="utf-8"></script>
</body>
</html>