There are several ways to include CSS in an HTML document. One way to include CSS in an HTML document is to use the `<style>` element.

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- The **advantage** of using the `<style>` element is that it allows you to define styles that apply to the entire document in one place;
- The **disadvantage** is that it can make your HTML document challenging to read and maintain since all your styles are mixed in with your HTML code. 

CSS, or Cascading Style Sheets, is a stylesheet language used to describe the presentation of a document written in a markup language like HTML. CSS is a fundamental building block of the modern web and controls the styling and layout of websites and web applications.

This section will cover the basics of CSS. You will learn the language's syntax, the most common CSS properties, and how to add CSS styles to your web page.

Selecting the elements you need becomes more challenging as your HTML code's complexity grows. This section will cover more advanced techniques of the selection.

This section will cover the general styling used for layout and text formatting to create a visually appealing and user-friendly design for your webpage. Part I.

Introduction to CSS Part I

Including CSS: Internal Styles