I'm pretty good at handling the cascade and knowing how things work, so this experience you are describing is not mine where CSS is concerned, I doubt I've had to do several hours of trying to make sense of any CSS for probably 5-6 years.
As such that the game does not actually allow you to use the cascade as it should be used is a downside.
"I understand cascading and so I know it isn't what should be done with Cascading StyleSheets. It is right this tool to simulate CSS doesn't support CSS' nominative feature "
I'm glad we agree CSS is unintuitive on many unique and creative fronts.