less

Less.js

The dynamic stylesheet language. lesscss.org

Less extends CSS with variables, mixins, functions, nesting, and more — then compiles to standard CSS. Write cleaner stylesheets with less code.

@primary: #4a90d9;

.button {
  color: @primary;
  &:hover {
    color: darken(@primary, 10%);
  }
}

Install

npm install less

Usage

Node.js

import less from 'less';

const output = await less.render('.class { width: (1 + 1) }');
console.log(output.css);

Command Line

npx lessc styles.less styles.css

Browser

<link rel="stylesheet/less" type="text/css" href="styles.less" />
<script src="https://cdn.jsdelivr.net/npm/less"></script>

Why Less?

• Variables — define reusable values once
• Mixins — reuse groups of declarations across rulesets
• Nesting — mirror HTML structure in your stylesheets
• Functions — transform colors, manipulate strings, do math
• Imports — split stylesheets into manageable pieces
• Extend — reduce output size by combining selectors

Documentation

Full documentation, usage guides, and configuration options at lesscss.org.

Contributing

Less.js is open source. Report bugs, submit pull requests, or help improve the documentation.

See CONTRIBUTING.md for development setup.

License

Copyright (c) 2009-2025 Alexis Sellier & The Core Less Team Licensed under the Apache License.

Similar packages

Other packages similar to less

sass

Sass (Syntactically Awesome Stylesheets) is a mature, stable, and powerful professional grade CSS extension language. It provides similar features to Less, such as variables, mixins, and nested rules. Sass has two syntaxes: the original 'indent' syntax that is similar to Haml and the newer 'SCSS' that uses braces like CSS. It's one of the most popular CSS preprocessors.

stylus

Stylus is a preprocessor that offers a mix of features from both Sass and Less, as well as some additional unique features. It has a more flexible syntax that can be written with or without braces, colons, and semicolons. Stylus provides powerful and efficient stylesheet writing capabilities.

postcss

PostCSS is a tool for transforming CSS with JavaScript plugins. These plugins can lint your CSS, support variables and mixins, transpile future CSS syntax, inline images, and more. PostCSS is different from preprocessors like Sass and Less in that it's modular and can be configured to perform a wide variety of tasks.