Acorn is the public design system for the Firefox desktop browser, as well as our iOS and Android browsers. It’s a curated library of design and development decisions that built the Firefox you know and love. Acorn is for the global community of employees, contributors, and volunteers that make Firefox better every day.
Mighty oaks from little acorns grow.
Why ‘Acorn’? Besides being a preferred snack of red pandas (also known as firefoxes), an acorn is too heavy to be spread by the wind. Instead, it’s thanks to the tireless toiling of the forest’s smallest creatures that towering canopies of oak trees can grow.
We hope you’ll use this seed to grow Firefox and help the internet blossom into something better.
We’re just getting started
Over the years, Firefox has evolved. Acorn is more than just another redesign — it's a living system that will continue to evolve alongside our product offerings. We’re updating Acorn regularly, so come back to watch us grow in the open.

Explore Acorn
Styles
Colors, typography, and more visual styles
Content guidelines
How to write for Firefox
Components
User interface components for building Firefox interfaces
Resources
Additional reference materials and guidelines for designing Firefox interfaces