# Less.js
> The dynamic stylesheet language. [lesscss.org](http://lesscss.org)
Less extends CSS with variables, mixins, functions, nesting, and more — then compiles to standard CSS. Write cleaner stylesheets with less code.
```less
@primary: #4a90d9;
.button {
color: @primary;
&:hover {
color: darken(@primary, 10%);
}
}
```
## Install
```sh
npm install less
```
## Usage
### Node.js
```js
import less from 'less';
const output = await less.render('.class { width: (1 + 1) }');
console.log(output.css);
```
### Command Line
```sh
npx lessc styles.less styles.css
```
### Browser
```html
```
## 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](http://lesscss.org)**.
## Contributing
Less.js is open source. [Report bugs](https://github.com/less/less.js/issues), submit pull requests, or help improve the [documentation](https://github.com/less/less-docs).
See [CONTRIBUTING.md](https://github.com/less/less.js/blob/master/CONTRIBUTING.md) for development setup.
## License
Copyright (c) 2009-2025 [Alexis Sellier](http://cloudhead.io) & The Core Less Team
Licensed under the [Apache License](https://github.com/less/less.js/blob/master/LICENSE).
