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Low-level CSS Toolkit – the original Functional/Utility/Atomic CSS library


Low-level CSS toolkit – the original Functional CSS library

Build Status npm version

Lightning-Fast Modular CSS with No Side Effects

Basscss is a lightweight collection of immutable utilities designed for speed, clarity, performance, and scalability.


Basscss v8 is the final version of Basscss, which means no major, breaking changes will be introduced. Minor features and patches may be added, but due to the nature of this CSS approach, there are virtually no bugs in Basscss.


Code with Confidence

Using clear, humanized naming conventions, Basscss is quick to internalize and easy to reason about while speeding up development time with more scalable, more readable code.

No Side Effects

Things behave exactly as expected with immutable utilities and styles that follow the open/closed principle to help prevent common pitfalls with CSS.


Reusable, interoperable styles work like building blocks to lay the foundation for any stylesheet and can be mixed and matched in any number of combinations.

Designed for Design

Basscss strikes a balance between consistency and flexibility to allow for rapid prototyping and quick iterative changes when designing in the browser.

Responsive by Default

Basscss provides lightweight, performant styles and flexible utilities to design for any device and to help reduce boilerplate in stylesheets.


Modular and customizable typography and layout styles don’t dictate what things should look like and play well with other stylesheets and frameworks.

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Other Packages

Base styles

The core Basscss package does not include any base element styles. For an out-of-the-box solution, see:


In addition to the core modules, optional modules, including responsive margin, padding, layout, and typography styles, can be found here:


For a bundle with the core Basscss and all optional modules, see:





This library was largely inspired and influenced by the following people

MIT license