CSS, or Cascading Style Sheets, is a language used to define the visual presentation of HTML documents. It controls the layout, colors, fonts, and overall appearance of web content. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.

Basic CSS Syntax

A CSS rule consists of a selector and a declaration block. The selector points to the HTML element you want to style, while the declaration block contains one or more declarations separated by semicolons. Each declaration includes a CSS property name and a value, separated by a colon. A CSS stylesheet will contain many such rules, structured as follows:

For example, to set the background color of all <p> elements to red, you would write:

Ways to Include CSS

There are three primary methods to include CSS in HTML documents: