CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of HTML and XML documents on the web. It was first introduced in 1996 by the World Wide Web Consortium (W3C) as a way to separate the presentation of a web page from its content.

CSS allows web developers to control the appearance of their web pages, by defining the layout, colors, fonts, and other visual elements. It works by associating style rules with HTML elements, using selectors to target specific elements in the page.

A CSS rule consists of a selector and a set of style declarations. The selector specifies which HTML elements the style should apply to, while the style declarations define the appearance of those elements. For example, the following CSS rule sets the color of all

elements to red:

css Copy code p { color: red; } CSS provides a wide range of properties that can be used to control the appearance of web pages. Some of the most common properties include:

Font properties: controls the font family, size, weight, and style of text Color properties: controls the color of text, background, and borders Layout properties: controls the position, size, and spacing of elements Animation properties: controls the animation and transition effects on elements One of the key benefits of CSS is its ability to separate the presentation of a web page from its content. This separation allows developers to make changes to the appearance of a web page without affecting its underlying structure or content. It also makes it easier to maintain and update web pages, as changes to the style can be made in a separate CSS file, rather than having to update each individual HTML file.

CSS has evolved over the years, with new features and improvements being added in each version. The latest version, CSS3, includes a wide range of new features such as support for advanced layouts, animations, and effects.

In summary, CSS is a powerful and essential part of modern web development. It provides developers with a powerful tool for controlling the appearance of their web pages, while also promoting a separation of concerns between the presentation and content of the page.