fullscreen courses

Hi

I create my courses on storyline 360 and display them in moodle. Unfortunately, as you can see in the attachment, the main part of the course screen (marked in blue) is a small rectangle in the middle and the rest of the screen is just black. How can I have the main part as big as possible on the screen? I need it to be as big as it possibly can be and at the same time have it smartly resize responsively based on user's device and screen size so all viewers can have the best responsive experience? how is that possible?

Thanks