Questions about the less CSS preprocessor usage in Magento. It supercharges the CSS for the developers with extra features and gets compiled back to CSS in the front/back end to be processed by the browser like a normal CSS.

Less is an open-source stylesheet preprocessor that extends css with dynamic behavior such as variables, mixins, operations and functions. It was developed by Alexis Sellier, more commonly known as cloudhead and is now hosted on GitHub.

Less is written in JavaScript and can be run both on the client-side and the server-side (with Node.js, Rhino, etc.). The code compiles the Less syntax into CSS and thus what is ultimately rendered by the browser is CSS, not Less. The syntax itself is similar to CSS and you can use it seamlessly along with regular CSS. The file extension of Less files is .less.