Less

Description #

Less (Leaner Style Sheets) is a dynamic preprocessor style language that extends CSS with variables, mixins, functions, and nested rules, allowing more maintainable and scalable stylesheets.

History #

Less was created by Alexis Sellier in 2009 to bring programming-like features to CSS. Initially written in Ruby, it was later rewritten in JavaScript and is now widely used in front-end development workflows. It integrates easily with Node.js environments and has become a popular choice for styling dynamic web applications.

Hello World Code #

@text-color: #333;

body {
  color: @text-color;
}

How to Run #

Option 1: Online

• Less Compiler – BeautifyTools
• CodePen (Use as Preprocessor)
• JSFiddle – Select LESS from CSS dropdown

Option 2: Local

Install Node.js and Less:

npm install -g less

Compile:

lessc styles.less styles.css

Key Concepts #

1. Variables for reusable values
2. Nested rules for hierarchy
3. Mixins to reuse groups of styles
4. Functions and operations
5. Easy maintenance of large CSS files
6. Compiles into standard CSS
7. JavaScript-based and Node-friendly
8. Cross-browser compatible
9. Conditional logic support
10. Supports plugin extensions

Try It Online #

• Less Compiler
• CodePen – Set LESS as preprocessor
• JSFiddle – Use LESS in settings

Fun Facts #

• The name “Less” is a play on “CSS” — giving more functionality with less code.
• Bootstrap originally used Less before switching to Sass.
• Less allows calculations like width: (100% / 3); in styles.

Resources #

• Official Less Site
• Less GitHub Repo
• Less Cheatsheet
• Less Compiler Docs