The editor lets you do all sorts of stuff

Bhooks has a rich editor where you can write and customize your book, consisting of a text editor, a cover editor, and a style editor.

Do you see the maximize icon in the editor? We even have a distraction free mode, where the entire textarea goes fullscreen. With AutoSave enabled, you also don't have to care about your progress being lost because you forgot to save, so you're free to just write.