The Howdy Glossary

Cascading Style Sheets (CSS) is a style sheet language used to design the presentation of documents in HTML or XML. It separates document content from presentation elements like layout, colors, and fonts, thus improving accessibility and providing flexibility in defining visual characteristics. CSS's syntax involves selectors and property-value pairs that determine which elements a style affects and their appearance or behavior across different media types. The "cascading" nature of CSS allows rules to cascade in a set order, enabling consistent styling across web documents while accommodating necessary exceptions.

CSS was developed by Håkon Wium Lie and Bert Bos in 1996 at the World Wide Web Consortium (W3C). Lie proposed separating style from structure in web documents, collaborating with Bos to create CSS for achieving this separation. Their efforts led to the standardization of CSS as an essential component of web design and development. This separation allows developers to define styles independently of HTML or XML content, simplifying updates, maintenance, and enhancing content accessibility.

CSS Level 3 introduces new features like gradients, transitions, animations, multi-column layouts, and flexbox layout mode that enhance design capabilities for modern websites. While alternatives such as Sass or Less preprocessors offer advanced features like variables and functions for easier stylesheet authoring; CSS-in-JS libraries integrate directly within JavaScript code for dynamic styling; frameworks like Bootstrap expedite development with pre-designed components but limit customization compared to native CSS. Despite these options' benefits, CSS remains the core technology due to its widespread support across browsers/devices and its ability to deliver responsive, aesthetically pleasing designs while maintaining code clarity and site performance.