Tailwind v4 + shadcn/ui Production Stack

Production-tested: WordPress Auditor (https://wordpress-auditor.webfonts.workers.dev) Last Updated: 2025-12-04 Status: Production Ready ✅

Table of Contents

• Before You Start

• Quick Start

• Four-Step Architecture

• Dark Mode Setup

• Critical Rules

• Semantic Color Tokens

• Common Issues & Fixes

• File Templates

• Setup Checklist

• Advanced Topics

• Dependencies

• Tailwind v4 Plugins

• Reference Documentation

• When to Load References

⚠️ BEFORE YOU START (READ THIS!)

CRITICAL FOR AI AGENTS: If you're Claude Code helping a user set up Tailwind v4:

• Explicitly state you're using this skill at the start of the conversation

• Reference patterns from the skill rather than general knowledge

• Prevent known issues listed in reference/common-gotchas.md

• Don't guess - if unsure, check the skill documentation

USER ACTION REQUIRED: Tell Claude to check this skill first!

Say: "I'm setting up Tailwind v4 + shadcn/ui - check the tailwind-v4-shadcn skill first"

Why This Matters (Real-World Results)

Without skill activation:

• ❌ Setup time: ~5 minutes

• ❌ Errors encountered: 2-3 (tw-animate-css, duplicate @layer base)

• ❌ Manual fixes needed: 2+ commits

• ❌ Token usage: ~65k

• ❌ User confidence: Required debugging

With skill activation:

• ✅ Setup time: ~1 minute

• ✅ Errors encountered: 0

• ✅ Manual fixes needed: 0

• ✅ Token usage: ~20k (70% reduction)

• ✅ User confidence: Instant success

Known Issues This Skill Prevents

• tw-animate-css import error (deprecated in v4)

• Duplicate @layer base blocks (shadcn init adds its own)

• Wrong template selection (vanilla TS vs React)

• Missing post-init cleanup (incompatible CSS rules)

• Wrong plugin syntax (using @import or require() instead of @plugin directive)

All of these are handled automatically when the skill is active.

Quick Start (5 Minutes - Follow This Exact Order)

1. Install Dependencies

bun add tailwindcss @tailwindcss/vite

or: npm install tailwindcss @tailwindcss/vite

bun add -d @types/node

Note: Using pnpm for shadcn init due to known Bun compatibility issues

(bunx has "Script not found" and postinstall/msw problems)

pnpm dlx shadcn@latest init

2. Configure Vite

// vite.config.ts import { defineConfig } from 'vite' import react from '@vitejs/plugin-react' import tailwindcss from '@tailwindcss/vite' import path from 'path'

export default defineConfig({ plugins: [react(), tailwindcss()], resolve: { alias: { '@': path.resolve(__dirname, './src') } } })

3. Update components.json

{ "tailwind": { "config": "", // ← CRITICAL: Empty for v4 "css": "src/index.css", "cssVariables": true } }

4. Delete tailwind.config.ts

rm tailwind.config.ts # v4 doesn't use this file

The Four-Step Architecture (CRITICAL)

This pattern is mandatory - skipping steps will break your theme.

Step 1: Define CSS Variables at Root Level

/* src/index.css */ @import "tailwindcss";

:root { --background: hsl(0 0% 100%); /* ← hsl() wrapper required / --foreground: hsl(222.2 84% 4.9%); --primary: hsl(221.2 83.2% 53.3%); / ... all light mode colors */ }

.dark { --background: hsl(222.2 84% 4.9%); --foreground: hsl(210 40% 98%); --primary: hsl(217.2 91.2% 59.8%); /* ... all dark mode colors */ }

Critical Rules:

• ✅ Define at root level (NOT inside @layer base )

• ✅ Use hsl() wrapper on all color values

• ✅ Use .dark for dark mode (NOT .dark { @theme { } } )

Step 2: Map Variables to Tailwind Utilities

@theme inline { --color-background: var(--background); --color-foreground: var(--foreground); --color-primary: var(--primary); /* ... map ALL CSS variables */ }

Why This Is Required:

• Generates utility classes (bg-background , text-primary )

• Without this, bg-primary etc. won't exist

Step 3: Apply Base Styles

@layer base { body { background-color: var(--background); /* NO hsl() here */ color: var(--foreground); } }

Critical Rules:

• ✅ Reference variables directly: var(--background)

• ❌ Never double-wrap: hsl(var(--background))

Step 4: Result - Automatic Dark Mode

<div className="bg-background text-foreground"> {/* No dark: variants needed - theme switches automatically */} </div>

Dark Mode Setup

1. Create ThemeProvider

See reference/dark-mode.md for full implementation or use template:

// Copy from: templates/theme-provider.tsx

2. Wrap Your App

// src/main.tsx import { ThemeProvider } from '@/components/theme-provider'

ReactDOM.createRoot(document.getElementById('root')!).render( <React.StrictMode> <ThemeProvider defaultTheme="dark" storageKey="vite-ui-theme"> <App /> </ThemeProvider> </React.StrictMode>, )

3. Add Theme Toggle

pnpm dlx shadcn@latest add dropdown-menu

See reference/dark-mode.md for ModeToggle component code.

Critical Rules (MUST FOLLOW)

✅ Always Do:

Wrap color values with hsl() in :root and .dark

--background: hsl(0 0% 100%); /* ✅ Correct */

Use @theme inline to map all CSS variables

@theme inline { --color-background: var(--background); }

Set "tailwind.config": "" in components.json

{ "tailwind": { "config": "" } }

Delete tailwind.config.ts if it exists

Use @tailwindcss/vite plugin (NOT PostCSS)

Use cn() for conditional classes

import { cn } from "@/lib/utils" <div className={cn("base", isActive && "active")} />

❌ Never Do:

Put :root or .dark inside @layer base

/* WRONG */ @layer base { :root { --background: hsl(...); } }

Use .dark { @theme { } } pattern

/* WRONG - v4 doesn't support nested @theme */ .dark { @theme { --color-primary: hsl(...); } }

Double-wrap colors

/* WRONG */ body { background-color: hsl(var(--background)); }

Use tailwind.config.ts for theme colors

/* WRONG - v4 ignores this */ export default { theme: { extend: { colors: { primary: 'hsl(var(--primary))' } } } }

Use @apply directive (deprecated in v4)

Use dark: variants for semantic colors

/* WRONG */ <div className="bg-primary dark:bg-primary-dark" />

/* CORRECT */ <div className="bg-primary" />

Semantic Color Tokens

Always use semantic names for colors:

:root { --destructive: hsl(0 84.2% 60.2%); /* Red - errors, critical / --success: hsl(142.1 76.2% 36.3%); / Green - success states / --warning: hsl(38 92% 50%); / Yellow - warnings / --info: hsl(221.2 83.2% 53.3%); / Blue - info, primary */ }

Usage:

<div className="bg-destructive text-destructive-foreground">Critical</div> <div className="bg-success text-success-foreground">Success</div> <div className="bg-warning text-warning-foreground">Warning</div> <div className="bg-info text-info-foreground">Info</div>

Common Issues & Quick Fixes

Symptom Cause Fix

bg-primary doesn't work Missing @theme inline mapping Add @theme inline block

Colors all black/white Double hsl() wrapping Use var(--color) not hsl(var(--color))

Dark mode not switching Missing ThemeProvider Wrap app in <ThemeProvider>

Build fails tailwind.config.ts exists Delete the file

Text invisible Wrong contrast colors Check color definitions in :root /.dark

See reference/common-gotchas.md for complete troubleshooting guide.

File Templates

All templates are available in the templates/ directory:

• index.css - Complete CSS setup with all color variables

• components.json - shadcn/ui v4 configuration

• vite.config.ts - Vite + Tailwind plugin setup

• tsconfig.app.json - TypeScript with path aliases

• theme-provider.tsx - Dark mode provider with localStorage

• utils.ts - cn() utility for class merging

Copy these files to your project and customize as needed.

Complete Setup Checklist

• Vite + React + TypeScript project created

• @tailwindcss/vite installed (NOT postcss)

• vite.config.ts uses tailwindcss() plugin

• tsconfig.json has path aliases configured

• components.json exists with "config": ""

• NO tailwind.config.ts file exists

• src/index.css follows v4 pattern:

• :root and .dark at root level (not in @layer)

• Colors wrapped with hsl()

• @theme inline maps all variables

• @layer base uses unwrapped variables

• Theme provider installed and wrapping app

• Dark mode toggle component created

• Test theme switching works in browser

Advanced Topics

Load references/advanced-usage.md for advanced patterns including:

• Custom Colors: Add semantic colors beyond default palette

• v3 Migration: See references/migration-guide.md for complete guide

• Component Best Practices: Semantic tokens, cn() utility, composition patterns

Quick Example:

:root { --brand: hsl(280 65% 60%); } @theme inline { --color-brand: var(--brand); }

Usage: <div className="bg-brand">Branded</div>

For detailed patterns and component composition examples, load references/advanced-usage.md .

Dependencies

✅ Install These

{ "dependencies": { "tailwindcss": "^4.1.17", "@tailwindcss/vite": "^4.1.17", "clsx": "^2.1.1", "tailwind-merge": "^3.3.1", "@radix-ui/react-*": "latest", "lucide-react": "^0.554.0", "react": "^19.2.0", "react-dom": "^19.2.0" }, "devDependencies": { "@types/node": "^24.10.1", "@vitejs/plugin-react": "^5.1.1", "vite": "^7.2.4", "typescript": "~5.9.3" } }

❌ NEVER Install These (Deprecated in v4)

These packages will cause build errors:

bun add tailwindcss-animate # ❌ Deprecated

or: npm install tailwindcss-animate # ❌ Deprecated

bun add tw-animate-css # ❌ Doesn't exist

If you see import errors for these packages, remove them and use native CSS animations or @tailwindcss/motion instead.

Tailwind v4 Plugins

Tailwind v4 supports official plugins using the @plugin directive in CSS.

Quick Example:

@import "tailwindcss"; @plugin "@tailwindcss/typography"; @plugin "@tailwindcss/forms";

Common Error: ❌ WRONG: @import "@tailwindcss/typography" (doesn't work) ✅ CORRECT: @plugin "@tailwindcss/typography" (use @plugin directive)

Built-in Features: Container queries are now core (no @tailwindcss/container-queries plugin needed).

Load references/plugins-reference.md for complete documentation including Typography plugin (prose classes), Forms plugin, installation steps, and common plugin errors.

Reference Documentation

For deeper understanding, see:

• common-gotchas.md - All the ways it can break (and fixes)

• dark-mode.md - Complete dark mode implementation

• migration-guide.md - Migrating hardcoded colors to CSS variables

• plugins-reference.md - Official Tailwind v4 plugins (Typography, Forms)

• advanced-usage.md - Custom colors and advanced patterns

When to Load References

Load reference files based on user's specific needs:

Load references/common-gotchas.md when:

• User reports "colors not working" or "bg-primary doesn't exist"

• Dark mode not switching properly

• Build fails with Tailwind errors

• User encounters any CSS/configuration issue

• Debugging theme problems

Load references/dark-mode.md when:

• User asks to implement dark mode

• Theme switching not working

• Need ThemeProvider component code

• Questions about system theme detection

Load references/migration-guide.md when:

• Migrating from Tailwind v3 to v4

• User has hardcoded colors to migrate

• Questions about v3 → v4 changes

• Need migration checklist

Load references/plugins-reference.md when:

• User needs Typography plugin (prose class)

• User needs Forms plugin

• Questions about @plugin directive

• Plugin installation errors

Load references/advanced-usage.md when:

• User asks about custom colors beyond defaults

• Need advanced component patterns

• Questions about component best practices

• Component composition questions

Official Documentation

• shadcn/ui Vite Setup: https://ui.shadcn.com/docs/installation/vite

• shadcn/ui Tailwind v4 Guide: https://ui.shadcn.com/docs/tailwind-v4

• shadcn/ui Dark Mode (Vite): https://ui.shadcn.com/docs/dark-mode/vite

• Tailwind v4 Docs: https://tailwindcss.com/docs

• shadcn/ui Theming: https://ui.shadcn.com/docs/theming

Production Example

This skill is based on the WordPress Auditor project:

• Live: https://wordpress-auditor.webfonts.workers.dev

• Stack: Vite + React 19 + Tailwind v4 + shadcn/ui + Cloudflare Workers

• Dark Mode: Full system/light/dark support

• Version: Tailwind v4.1.17 + shadcn/ui latest (Nov 2025)

All patterns in this skill have been validated in production.

Questions? Issues?

• Check reference/common-gotchas.md first

• Verify all steps in the 4-step architecture

• Ensure components.json has "config": ""

• Delete tailwind.config.ts if it exists

• Check official docs: https://ui.shadcn.com/docs/tailwind-v4