What is CSS?

• CSS stands for Cascading Style Sheets
• Styles define how to display HTML elements
• Styles are normally stored in Style Sheets
• Styles were added to HTML 4.0 to solve a problem
• External Style Sheets can save you a lot of work
• External Style Sheets are stored in CSS files
• Multiple style definitions will cascade into one

CSS stands for Cascading Style Sheets. It is a way to divide the content from the layout on web pages.

How it works:

A style is a definition of fonts, colors, etc.

Each style has a unique name: a selector.

The selectors and their styles are defined in one place.

In your HTML contents you simply refer to the selectors whenever you want to activate a certain style.

For example:

Instead of defining fonts and colors each time you start a new table cell, you can define a style and then, simply refer to that style in your table cells.

Compare the following examples of a simple table:

Classic HTML

this is line 1 this is line 2 this is line 3

With CSS (assuming that a selector called subtext is defined)

this is line 1 this is line 2 this is line 3

While CSS lets you separate the layout from the content, it also lets you define the layout much more powerfully than you could with classic HTML.