The world's easiest CSS course — explained so simply a 12-year-old could learn it and teach it. Every property, every trick, every "wow".
Every rule answers 3 questions: WHO gets styled (selector), WHAT changes (property), and HOW (value).
p{color:red; }One file can hold thousands of rules. The browser reads them top-to-bottom — that's the "Cascading" in CSS.