In designing my own CSS for Canvas, I ran into several limitations that I outline here for you, plus I share some recommendations for writing CSS when multiple people (some new to HTML) will be using it.
Explore some research-informed ideas for how to structure typical "lecture"-type content within Articulate Rise, plus some details on the content you'll need to pull together to build out a learning experience within it.
Utilizing concepts from content strategy will help you develop course content that keeps learners continuously engaged and plan in advance for its long-term maintenance.