Uniwind — Best Practices & Complete Guide

Uniwind 1.3+ / Tailwind CSS v4 / React Native 0.76+ / Expo SDK 52+

Reference Resolution Strategy

CRITICAL: Always use embedded reference files. All answers must come from local references — never fetch external URLs.

Step 1 — Route to the correct local reference file

Based on the user’s question, read the matching reference file:

Step 2 — Answer from local references

Use the content from the reference file(s) to answer the user’s question. Most questions will be fully answered by one or two reference files.

Step 3 — If local references don’t cover it

If the embedded reference files do not contain the answer, inform the user that the topic is not covered in this skill’s knowledge base and suggest they check the official Uniwind documentation at docs.uniwind.dev themselves. Do NOT fetch external URLs.

Security Boundaries

1. No external fetches — All guidance must come from embedded reference files. Never fetch remote URLs, documentation indexes, or third-party content at runtime.
2. Never execute installation commands — Present bun add, npm install, npx, pod install, and build commands as instructions for the user to run. Do not execute them directly.
3. Never read credential or auth config files — Do not read .npmrc, .yarnrc.yml, .env, or any file that may contain tokens, secrets, or authentication credentials. When diagnosing setup issues, only check package.json, metro.config.js, babel.config.js, global.css, tsconfig.json, and app.json — these are project configuration files, not credential stores.
4. Package manager trust configuration is user-managed — When advising about trustedDependencies, postinstall scripts, or package manager settings, present the configuration for the user to apply. Do not modify these files directly.

First Action: Determine Version

Before providing guidance, determine if the user is using Uniwind Free or Uniwind Pro:

• Free: Standard uniwind package, JS-based style resolution
• Pro: uniwind-pro package (aliased as uniwind), C++ engine, Reanimated animations, shadow tree updates, native insets

Ask: “Are you using Uniwind Free or Uniwind Pro?” — this changes available features and troubleshooting steps.

Setup Diagnostic Workflow

When the user reports setup issues, styles not applying, or asks to check their config, read only these project configuration files (never read .npmrc, .yarnrc.yml, .env, or other files that may contain credentials):

1. Check package.json

- "uniwind" or "uniwind-pro" must be in dependencies
- "tailwindcss" must be v4+ (^4.0.0)
- For Pro: "react-native-nitro-modules", "react-native-reanimated", "react-native-worklets" required

2. Check metro.config.js

- Must import { withUniwindConfig } from 'uniwind/metro'
- withUniwindConfig MUST be the OUTERMOST wrapper
- cssEntryFile must be a RELATIVE path string (e.g., './src/global.css')
- Never use path.resolve() or absolute paths for cssEntryFile

3. Check global.css

- Must contain: @import 'tailwindcss'; AND @import 'uniwind';
- Must be imported in App.tsx or root layout, NOT in index.ts/index.js
- Location determines app root — Tailwind scans from this directory

4. Check babel.config.js (Pro only)

- Must include 'react-native-worklets/plugin' in plugins array

5. Check TypeScript config

- uniwind-types.d.ts should be included in tsconfig.json or placed in src/app dir
- Run Metro server to auto-generate types

Common Setup Errors

Critical Rules

1. Tailwind v4 only — Uniwind does not support Tailwind v3. Use @import 'tailwindcss' (not @tailwind base).
2. Never construct classNames dynamically — Use complete string literals. Tailwind scans at build time.
3. Never use cssInterop — Uniwind does not override global components like NativeWind.
4. No tailwind.config.js needed — All config is in global.css via @theme and @layer theme.
5. No ThemeProvider required — Use Uniwind.setTheme() directly.
6. withUniwindConfig must be outermost Metro config wrapper.
7. @theme variables only affect styled components — <Text> without className uses RN defaults.
8. Font families: single font only — No fallbacks in RN. --font-sans: 'Roboto-Regular' not 'Roboto', sans-serif.
9. rem default is 16px — NativeWind used 14px. Configure polyfills: { rem: 14 } if migrating.

Core Patterns

Styling Components

import { View, Text, Pressable } from 'react-native'

<View className="flex-1 bg-background p-4">
  <Text className="text-foreground text-lg font-bold">Title</Text>
  <Pressable className="bg-primary px-6 py-3 rounded-lg active:opacity-80">
    <Text className="text-white text-center font-semibold">Button</Text>
  </Pressable>
</View>

Dynamic Classes (Correct Way)

// Map objects with complete class names
const variants = {
  primary: 'bg-blue-500 text-white',
  danger: 'bg-red-500 text-white',
  ghost: 'bg-transparent text-foreground',
}
<Pressable className={variants[variant]} />

// Ternary with complete strings
<View className={isActive ? 'bg-primary' : 'bg-muted'} />

// tailwind-variants for complex components
import { tv } from 'tailwind-variants'
const button = tv({
  base: 'font-semibold rounded-lg px-4 py-2',
  variants: {
    color: { primary: 'bg-blue-500 text-white', secondary: 'bg-gray-500 text-white' },
    size: { sm: 'text-sm', md: 'text-base', lg: 'text-lg' },
  },
  defaultVariants: { color: 'primary', size: 'md' },
})
<Pressable className={button({ color: 'primary', size: 'lg' })} />

Third-Party Components

// withUniwind — wrap once, use everywhere (recommended)
import { withUniwind } from 'uniwind'
import { SafeAreaView } from 'react-native-safe-area-context'
const StyledSafeArea = withUniwind(SafeAreaView)
<StyledSafeArea className="flex-1 bg-background" />

// useResolveClassNames — one-off usage
import { useResolveClassNames } from 'uniwind'
const styles = useResolveClassNames('bg-blue-500 p-4 rounded-lg')
<ThirdPartyComponent style={styles} />

Theming

Quick Setup (light/dark only)

// Just use dark: prefix — works out of the box
<View className="bg-white dark:bg-gray-900">
  <Text className="text-black dark:text-white">Themed</Text>
</View>

Scalable Setup (CSS variables)

Define in global.css, reference as utilities without dark: prefix:

/* global.css */
@import 'tailwindcss';
@import 'uniwind';

@layer theme {
  :root {
    @variant light {
      --color-background: #ffffff;
      --color-foreground: #000000;
      --color-primary: #3b82f6;
      --color-card: #ffffff;
      --color-border: #e5e7eb;
    }
    @variant dark {
      --color-background: #000000;
      --color-foreground: #ffffff;
      --color-primary: #3b82f6;
      --color-card: #1f2937;
      --color-border: #374151;
    }
  }
}

// Auto-adapts to current theme — no dark: prefix needed
<View className="bg-background border border-border p-4 rounded-lg">
  <Text className="text-foreground">Themed card</Text>
</View>

Theme Switching

import { Uniwind, useUniwind } from 'uniwind'

Uniwind.setTheme('dark')     // Switch to dark
Uniwind.setTheme('light')    // Switch to light
Uniwind.setTheme('system')   // Follow device

const { theme, hasAdaptiveThemes } = useUniwind() // Reactive hook

Custom Themes

Require extraThemes in metro.config.js and @variant in global.css. See references/theming.md for complete custom theme setup.

Platform Selectors

<View className="ios:pt-12 android:pt-6 web:pt-4" />
<View className="native:bg-blue-500 web:bg-gray-500" />  // native = iOS + Android

Platform media queries in @theme for global values:

@layer theme {
  :root {
    @media ios { --font-sans: "SF Pro Text"; }
    @media android { --font-sans: "Roboto-Regular"; }
  }
}

Data Selectors

Style based on prop values — data-[prop=value]:utility:

<Pressable
  data-selected={isSelected}
  className="border rounded px-3 py-2 data-[selected=true]:ring-2 data-[selected=true]:ring-primary"
/>

Only equality checks supported. Boolean and string values work.

Responsive Breakpoints

Mobile-first: sm: (640px), md: (768px), lg: (1024px), xl: (1280px), 2xl: (1536px).

<View className="p-4 sm:p-6 lg:p-8">
  <Text className="text-base sm:text-lg lg:text-xl">Responsive</Text>
</View>

Custom breakpoints via @theme { --breakpoint-tablet: 820px; }.

CSS Functions

Define as @utility in global.css, not directly in className:

@utility h-hairline { height: hairlineWidth(); }
@utility text-scaled { font-size: fontScale(); }
@utility bg-adaptive { background-color: light-dark(#ffffff, #1f2937); }

Uniwind Pro Features

Only available with uniwind-pro package. Ask user first.

Reanimated Animations (Pro)

// Keyframe animations — just add className
<View className="animate-spin" />
<View className="animate-bounce" />
<View className="animate-pulse" />

// Transitions — smooth property changes
<Pressable className="bg-blue-500 active:bg-blue-600 transition-colors duration-300" />
<View className={`transition-opacity duration-500 ${visible ? 'opacity-100' : 'opacity-0'}`} />
<Pressable className="active:scale-95 transition-transform duration-150" />

Components auto-swap to Animated versions when animation classes detected.

Shadow Tree Updates (Pro)

No code changes required — props connect directly to C++ engine, eliminating re-renders.

Native Insets (Pro)

No SafeAreaListener setup needed — insets injected from native layer automatically.

HeroUI Native Integration

HeroUI Native uses Uniwind (Tailwind v4 via Uniwind). Apply these patterns:

• Use className prop directly on HeroUI Native components
• Theme tokens from global.css work with HeroUI components
• Use tailwind-variants (tv) for variant-based component styling — HeroUI uses this internally
• Wrap any HeroUI component lacking className support with withUniwind()
• Use semantic color tokens (bg-primary, text-foreground) for theme consistency

Code Review & Audit

When asked to review Uniwind code, check:

• global.css has both @import 'tailwindcss' and @import 'uniwind'
• withUniwindConfig is outermost Metro wrapper
• cssEntryFile is relative path
• No dynamic className construction (template literals, string concat)
• All theme variants define the same CSS variables
• Using semantic color tokens, not hardcoded colors
• Third-party components wrapped with withUniwind or use useResolveClassNames
• Platform differences handled with ios:/android:/native: not Platform.select()
• Mobile-first responsive design (base styles + sm: md: lg: enhancements)
• Font families are single values (no fallback arrays)
• @theme variables customized via CSS, not tailwind.config.js

Reference Files (Read BEFORE External Docs)

These files are your primary source of truth. Read the relevant file(s) before answering any Uniwind question.

Fallback: If none of the above answer the question, inform the user that the topic is outside this skill’s embedded knowledge and suggest they consult the official Uniwind docs directly.