Ok but needs refining
1. It doesn’t remember the page you were on previously - this is a major time waster and serious usability oversight.
2. Single page viewing in landscape orientation does make use of full screen width, cutting off the page as you zoom in to read something (2 page mitigates this for some reason)
3. In app ui and controls are tiny
4. The ui elements fade back in far too easily - single corner button to dismiss/show would solve this.
All up not bad and great to read complementary to course materials.