Responsive Web Design (RWD) is an approach to web development that ensures a website's layout and content adapt seamlessly to various screen sizes and devices. This technique enhances user experience by providing optimal viewing conditions, whether on a desktop, tablet, or smartphone. By utilizing flexible grids, images, and CSS media queries, RWD allows developers to create a single website that functions well across multiple platforms. This not only improves accessibility but also boosts search engine rankings, as search engines favor mobile-friendly sites. Overall, RWD is essential for modern web design.