Reader’s Firefox browser has a setup mode, but they are very few. By default, you can only select the type of text (serif or without), change the size of the letters and switch the view of the page background. The situation changed dramatically after the installation of expansion Better Reader.
Now you can choose from any font installed on your system, increase or decrease the column width, adjust the size of the letters. The colors of text, backgrounds, links and other elements on the page can also be set up on your own, and then save the created color schemes to quickly switch between them.
Better Reader is free and available for download in Firefox add-ons directory. Be sure to try this extension, if you read a lot and want to make it the most comfortable way.