UI8Kit — Ultra-Fast UI System

A minimal, high-performance UI system combining React Strict DOM, Tailwind-style utilities, and shadcn color tokens.

🎯 Philosophy

Zero overhead, maximum speed.

• < 2KB runtime with React Strict DOM
• No CSS files — styles injected inline via StyleX
• 13 components cover 80% of UI needs
• Tailwind syntax without Tailwind overhead

🏗️ Architecture

┌─────────────────────────────────────────────────────────────┐
│                      Your Application                        │
├─────────────────────────────────────────────────────────────┤
│  UI8Kit Components    │  RSD Layouts + TWSX                 │
│  (Button, Card, etc.) │  (html.div, twsx('flex gap-4'))     │
├───────────────────────┴─────────────────────────────────────┤
│                    shadcn Color Tokens                       │
│     (--primary, --background, --foreground, etc.)           │
├─────────────────────────────────────────────────────────────┤
│                   React Strict DOM (RSD)                     │
│              (< 2KB, atomic CSS, cross-platform)            │
└─────────────────────────────────────────────────────────────┘

📦 Three Layers

1. UI8Kit — Stateless Components

Pre-built components with CVA variants. No state, no hooks — pure styling.

import { Button, Stack, Title, Text } from '@ui8kit/ui'

<Stack gap="lg" align="center">
  <Title size="4xl">Welcome</Title>
  <Text c="muted">Build fast UIs</Text>
  <Button variant="primary">Get Started</Button>
</Stack>

2. RSD + TWSX — Custom Layouts

React Strict DOM elements with Tailwind-style utilities.

import { html } from 'react-strict-dom'
import { twsx } from '@/lib/twsx'

<html.div style={twsx('min-h-screen flex flex-col')}>
  <html.header style={twsx('w-full py-4 px-6 bg-background')} />
  <html.main style={twsx('flex-1 p-6 max-w-7xl mx-auto')} />
</html.div>

3. shadcn Colors — Design Tokens

Semantic color tokens via CSS variables.

:root {
  --background: hsl(0 0% 100%);
  --foreground: hsl(240 10% 4%);
  --primary: hsl(211 100% 50%);
  --secondary: hsl(210 40% 96%);
  --muted: hsl(210 40% 96%);
  --accent: hsl(210 40% 96%);
  --destructive: hsl(0 84% 60%);
}

🚀 Quick Start

# Clone with submodules
git clone --recurse-submodules https://github.com/ui8kit/create-app.git
cd create-app

# Install dependencies
bun install

# Start development
bun run dev:web

📁 Project Structure

apps/web/src/
├── components/ui/     # UI8Kit components (13)
├── variants/          # CVA variant definitions (12 modules)
├── lib/
│   ├── twsx.ts        # Tailwind → StyleX converter
│   └── utils.ts       # Utilities (cn, etc.)
├── layouts/           # RSD page layouts
└── blocks/            # RSD composite blocks

🎨 When to Use What

Need	Use	Example
Button, Badge, Card	UI8Kit	<Button variant="primary">
Page layout	RSD + TWSX	twsx('min-h-screen flex')
Grid system	RSD + TWSX	twsx('grid grid-cols-3 gap-4')
Custom block	RSD + TWSX	<html.section style={...}>
Colors	shadcn tokens	bg-primary, text-foreground

📚 Documentation

• 101 Guide — Complete introduction to the system
• AGENTS.md — Instructions for AI coding agents

🔧 Rules Files

Three Cursor rules define how to use the system:

1. .cursor/rules/react-strict-dom.mdc — RSD elements and css.create()
2. .cursor/rules/twsx.mdc — Tailwind syntax for RSD
3. .cursor/rules/ui8kit.mdc — Component library usage

⚡ Performance

Metric	Target
RSD Runtime	< 2KB gzipped
CSS Output	Atomic classes only
Bundle	Tree-shaken, no unused styles
First Paint	< 1.5s

📄 License

MIT License — see LICENSE for details.

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Built for speed. Designed for clarity. Zero overhead.