ion: column;
    display: flex;
    margin: 0;
    padding: 0;
  }

  body > tr-ui-timeline-view {
    flex: 1 1 auto;
    min-height: 0;
  }
  body > tr-ui-timeline-view:focus {
    outline: none;
  }
</style>
</head>
<body>
  <tr-ui-timeline-view>
    <track-view-container id='track_view_container'></track-view-container>
  </tr-ui-timeline-view>

  <script>
  'use strict';

  let timelineViewEl;
  let selectEl;

  function loadTraces(filenames, onTracesLoaded) {
    const loadTracesMark = tr.b.Timing.mar