CSS Preprocessors: CSS preprocessors are scripting languages that extend the default capabilities of CSS (Cascading Style Sheets) by allowing developers to write more efficient, reusable, and organized code. These preprocessors are compiled or processed into regular CSS code that browsers can understand. Popular CSS preprocessors include [Sass](https://sass-lang.com/), [LESS](http://lesscss.org/), and [Stylus](https://stylus-lang.com/). They introduce features such as variables, mixins, nesting, and mathematical functions, making it easier to maintain and scale large CSS files in web design and development projects.
