Below please find links to archived Q&A discussion for the CSS: An Overview course.
Exercise 1.1: Seeing is believing
Exercise 1.2: What CSS is
Exercise 1.3: Why separate form from function?
Exercise 1.4: If it's in, it's out!
Exercise 1.5: Link it up!
Exercise 1.6: PSA: Self-closing tags
Exercise 2.1: Syntax for the wintax
Exercise 2.2: One selector, many properties
Exercise 2.3: Many selectors, many properties
Exercise 2.4: The importance of semicolons
Exercise 2.5: Color commentary
Exercise 2.6: Check yourself before you wreck yourself