What is CSS and what does it do?

CSS stands for Cascading Style Sheets. It controls the look and layout of HTML elements on a webpage, such as colours, fonts, spacing, and positioning.

How do I link a CSS file to my HTML document?

Use the tag inside the section of your HTML like this:

What’s the difference between classes and IDs in CSS?

Classes (using a .) can be used on multiple elements, while IDs (using a #) should be unique and only used once per page.

What is a CSS selector?

A CSS selector targets the HTML element(s) you want to style. For example, p targets all paragraphs, and .highlight targets all elements with the class "highlight".