---
title: Introduction to CSS
---

## Table of Contents

* [Introduction to CSS](#introduction-to-css)
* [What is CSS?](#what-is-css)
* [Using CSS](#using-css)
* [More Information](#more-information)

## Introduction to CSS

### What is CSS?

Cascading Style Sheets (CSS) describe how the html on a page should appear.

Before CSS developers would apply styles using attributes or special tags on each node of a page. This made markup repetitive and prone to errors.

CSS allows selectors to describe how each piece of matching content should look.

```CSS
body {
    font-size: 15px;
}

a {
    color: rebeccapurple;
    text-decoration: underline;
}
```

### Using CSS

**External style sheets** let many pages share the same styles.

```HTML
<link href="styles.css" rel="stylesheet" type="text/css">
```

**Internal style sheets** apply CSS to all matching tags on a page.

```HTML
<style>
    h1 {
        font-family: sans-serif;
        margin-bottom: 1.5em;
    }
</style>
```

**Inline CSS** apply styles to a single tag.

```HTML
<img src="..." style="border: 1px solid red;" />
```

#### More Information:
* [W3Schools](https://www.w3schools.com/css/css_intro.asp)
* [CSS-Tricks Almanac](https://css-tricks.com/almanac/)
* [Sitepoint](https://www.sitepoint.com/html-css/?ref_source=github)