Sass (Syntactically Awesome Style Sheets) is a preprocessor scripting language that is compiled or interpreted into Cascading Style Sheets (CSS). Sass is a superset of CSS, meaning that every valid CSS stylesheet is also a valid Sass file. Sass extends CSS by adding features such as variables, nested rules, mixins, functions, and inheritance, which are not available in standard CSS. These features allow developers to write more modular, maintainable, and efficient CSS code. Sass helps to reduce code duplication and makes it easier to manage large stylesheets. It provides a more structured and organized approach to CSS development, leading to cleaner and more readable code. Sass files typically use the .sass or .scss extension. The .sass syntax uses indentation to define code blocks, while the .scss syntax uses curly braces and semicolons, similar to CSS. Sass is widely used in web development for creating complex and dynamic stylesheets.