Watch: Please view the following 8-minute video by Edureka, a popular YouTube channel that aims to make learning accessible by creating coding tutorials and technical explanation videos on all sorts of topics in software. In this video, they introduce some fundamental concepts of CSS and explain how it is used alongside HTML.
Additional Resource: For students who learn better through reading, here is an article, also created by Edureka, that teaches the basics of CSS: What is CSS? – The Style Statement of the Internet