Why is the actual lesson text less than 1/4th of the screen on the desktop version?

Is there a way to expand it? It’s incredibly difficult to study when it’s so small and I can’t even scroll the main window to bring the small lesson box up to the top of the screen, so it’s just stuck down at the bottom. Any help would be appreciated.

After you open a lesson, click on the settings button (gear icon) on the top right, and there you will find an option to control page size.