Nice, I would love to see better use of large screens, such as demonstrated in this demo. This reminds me of the pressreader.com UI. Some feedback: You're show

Nice, I would love to see better use of large screens, such as demonstrated in this demo. This reminds me of the pressreader.com UI. Some feedback: You're showing heading of the last section on the right edge ("Note-writing practices are generally ineffective"). This probably isn't the most useful one - the reader is more interested in the "next" section rather than the last one. Or show all of them, like you do on the left edge. Offer a way to skip to a section by clicking its collapsed card.