**CSS**, or Cascading Style Sheets, is a style sheet language used to describe a document's look and formatting in a markup language. It is most commonly used to style web pages written in HTML and XHTML but can also be applied to any XML document, including SVG and XUL.

For example, the following CSS code defines a style for a heading element, specifying that it should be displayed in a `bold`, `24-point` font:

```css
h1 {
  font-weight: bold;
  font-size: 24pt;
}
```

To apply this style to a heading element on a web page, we simply need to include the appropriate HTML tag and specify the `class` or `id` of the style we want to use, like so:

```html
<h1 class="heading">My Heading</h1>
```

We can use a `class` selector to apply the above style to any element with a class of `heading`, like so:

```css
.heading {
  font-weight: bold;
  font-size: 24pt;
}
```

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

CSS