What is CSS?
Cascading Style Sheets (CSS) is used to format the layout of a webpage. With CSS, you can control the color, font, the size of text, the spacing between elements, how elements are positioned and laid out, what background images or background colors are to be used, and different displays for different devices and screen sizes.
The word cascading means that a style applied to a parent element will also apply to all children elements within the parent. So, if you set the color of the body text to "blue," all headings, paragraphs, and other text elements within the body will also get the same color (unless you specify something else)!
Using CSS
CSS can be added to HTML documents in 3 ways:
- Inline - by using the style attribute inside HTML elements
- Internal - by using a <style> element in the <head> section
- External - by using a <link> element to link to an external CSS file
The most common way to add CSS is to keep the styles in external CSS files. However, in this tutorial, we will use inline and internal styles because this is easier to demonstrate and easier for you to try it yourself.
Inline CSS
An inline CSS is used to apply a unique style to a single HTML element. An inline CSS uses the style attribute of an HTML element. The following example sets the text color of the <h1> element to blue and the text color of the <p> element to red:
<h1 style="color:blue;">A Blue Heading</h1>
<p style="color:red;">A red paragraph.</p>Internal CSS
An internal CSS is used to define a style for a single HTML page. An internal CSS is defined in the <head> section of an HTML page, within a <style> element.
The following example sets the text color of all <h1> elements on that page to blue and the text color of all <p> elements to red. Additionally, the page will be displayed with a "powderblue" background color:
<!DOCTYPE html>
<html>
<head>
<style>
body {
background-color: powderblue;
}
h1 {
color: blue;
}
p {
color: red;
}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>External CSS
An external style sheet is used to define the style for many HTML pages. To use an external style sheet, add a link to it in the <head> section of each HTML page:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>