Cascading Style Sheets

Cascading Style Sheets. It is a cornerstone technology of the World Wide Web, used alongside HTML and JavaScript to define the visual presentation of web pages. Developed to separate content from design, it allows web designers to control layout, colors, fonts, and responsiveness across an entire site from a single file. Its specifications are maintained by the World Wide Web Consortium (W3C) and have evolved through several levels, fundamentally shaping the modern user experience on platforms like Google, Facebook, and Wikipedia.

History

The concept was first proposed in 1994 by Håkon Wium Lie while working at CERN with Tim Berners-Lee, with significant contributions later from Bert Bos. The first official recommendation, CSS Level 1, was published by the World Wide Web Consortium in 1996. Browser adoption was initially fragmented, with early support from Internet Explorer 3 and Netscape Navigator 4 leading to the infamous Browser wars. The more robust CSS Level 2 recommendation followed in 1998, with CSS 2.1 becoming a formal standard in 2011. Subsequent modular development, known as CSS3, introduced features like CSS Animations and CSS Grid Layout, with ongoing work by the CSS Working Group.

Syntax

A CSS rule-set consists of a selector and a declaration block enclosed in curly braces. Declarations are property-value pairs separated by a colon and terminated by a semicolon, such as `color: blue;`. These rules can be placed within an HTML document using the `