Bulma - Bulma is an open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.
Universal Book Reader - Just like its name, Universal Book Reader is really a universal book reading application allowing you to read the eBooks from the convenience of your smartphones.
Milligram - A minimalist CSS framework
Cool Reader - Fast and small cross-platform eBook reader for desktops and handheld devices
Spectre.css - Lightweight, responsive and modern CSS framework for faster and extensible development.
iReader - iReader is one of the most accomplished ways to read the books right from your smartphones.