Adapt course material and tests to mobile viewports

A lot of the content (images etc.) is hard to digest on a mobile due to images with very small text, some with vague contrast etc.

I think it is expected – when taking a course in accessibility – that the offered course material is adapted according to all best practices that are taught.
I really like the concept and the formats you have, but I think making the course material accessible for everyone would benefit your business. I, for one, have difficulties grasping everything without sitting in a rather dark environment with the screen brightness turned up and with reading glasses on.