What is the main purpose of Cascading Style Sheets (CSS) in web development?

The main purpose of Cascading Style Sheets (CSS) in web development is to define the look and formatting of a website. CSS allows developers to separate content from design, enabling them to control the layout, colors, fonts, and overall aesthetic of HTML elements on a web page. By using CSS, designers can apply styles consistently across multiple pages, streamline updates, and improve the efficiency of web design. This layering of style on top of content not only enhances the visual appeal but also facilitates better user experience and accessibility.

CSS plays a crucial role in responsive design, allowing webpages to adapt to different screen sizes and orientations, which is increasingly important in the mobile-first web environment. This focus on design and presentation, rather than functionality or data management, distinguishes CSS from other technologies commonly used in web development.