design for intention
and meaning

rnbw 🌈 is a design system for clean, lightweight interfaces, built to be ai-ready from the ground up. semantic class names and a utility-first approach make it fluent for ai design-to-code workflows while staying simple for humans. no weird stuff.

hand it to your agent

llms.txt ↗

your agent

plain html

build with rnbw.css. read https://rnbw.design/llms.txt first, then write plain html with its classes.

on it. one stylesheet, its classes, and plain html:

<main class="column gap-l padding-xl">
  <h1>full circle</h1>
  <p class="text-xl">design and code, one material.</p>
</main>

simple yet dangerous

simple enough for anyone, complex enough for anything, and open enough to use anyhow. rnbw is focusing on atomic concepts. when combined, they multiply their meaning.

rnbw's classes say what they do: text-xl, gap-l, inverse-primary. the designer names it, the developer writes it, ai reads it. describe a thing, and the classes that draw it are the design.

atoms

a class is one decision. combined, they multiply their meaning.

icons

197 icons, 12x12, in one sprite.

Aa

type

one face, one weight, a scale from text-s to h1.

motion

fade, slide, zoom, spin and pulse, at three speeds.

html, as it is

headings, lists, quotes, forms and code are styled before you add a class.

a 4px scale

xs, s, m, l, xl: every gap, padding, size and radius steps together.

optimized for openness

rnbw is open source under the mit license. every design decision in it is a commit you can read: what changed, who changed it, and why, in plain words.

build rnbw.css and icons.svg from src/ with one node script and no dependencies, and make it yours with tokens and themes: change the base size, the font unit or a colour, and the whole system follows.

open source

mit license. read every line of src/, and change any of it.

no dependencies

html, and the css that styles it. one node script builds rnbw.css, icons.svg and llms.txt from src/.

--base-size: 4px;
--font-unit: 1.25rem;
tokens

change the base size, the font unit or a colour, and the whole system follows.

the dev way

every design decision is a commit you can read: what changed, who, and why, in plain words.