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.
With this CSS, you can create more distinct titles and add an introduction section to pages in your Canvas course.
This code allows you to create a grid of images that can act as a menu; when you hover over one of the images, it transforms from grayscale to full color. I typically use this layout to create a menu of a course's modules on its front page.
I developed this header to add to the top of a Canvas course's homepage. It provides space for a quick text announcement, and it has a button that direct students to a specific spot in the course.
With accordions, you can include a lot of content on a page without taking up a lot of real estate. They work particularly well as FAQ lists and glossaries.