LESS

Leaner Style Sheets

A dynamic preprocessor style sheet language that extends standard CSS with additional features like variables, mixins, functions, and nested rules. It simplifies CSS development by making stylesheets more maintainable, reusable, and easier to scale.

Developers write LESS code in .less files, which are then compiled into standard CSS that browsers can interpret. LESS enables programming concepts within stylesheets, such as defining a color variable once and reusing it throughout a site, making global design changes fast and efficient.

LESS can be compiled on the server side, during a build process, or live in the browser using JavaScript (primarily in development environments).

Key Features of LESS:

• Variables: Store values like colors, font sizes, or spacing units to ensure consistency across stylesheets.
• Mixins: Reuse groups of CSS declarations across different selectors.
• Nesting: Organize CSS rules in a hierarchy that mirrors the structure of HTML, improving readability.
• Functions & Operations: Perform calculations and manipulate values directly within stylesheets (e.g., color functions like lighten() or darken()).
• Extends: Share sets of properties across selectors to avoid code duplication.

LESS was one of the first popular CSS preprocessors, influencing the development of others like SASS and Stylus. While SASS has become more dominant in many projects, LESS remains widely used, especially in projects and frameworks like Bootstrap (up until version 4).