Sass (Syntactically Awesome Style Sheets) is a preprocessor scripting language that is compiled or interpreted into Cascading Style Sheets (CSS). Sass extends CSS by adding features like variables, nested rules, mixins, functions, and inheritance, which are not available in standard CSS. These features allow developers to write more maintainable, reusable, and organized CSS code. Sass helps to reduce code duplication and makes it easier to manage large stylesheets. The two main syntaxes for Sass are SCSS (Sassy CSS), which uses a syntax similar to CSS, and indented syntax (also known as Sass), which uses indentation to define code blocks. SCSS files are typically saved with the .scss extension, while indented syntax files use the .sass extension. Both are compiled into standard CSS files that can be used by web browsers.