SCSS (Sassy CSS) is the most common syntax for Sass (Syntactically Awesome Style Sheets), a preprocessor scripting language that extends standard CSS with advanced programming features. It is a superset of CSS, meaning any valid CSS code is also valid SCSS, and it uses a familiar syntax with curly braces and semicolons.
Because browsers cannot interpret SCSS directly, files with the .scss extension must be compiled into standard .css files using a Sass compiler.