Shadcn Setup

shadcn/ui Setup

Sets up shadcn/ui with proper Tailwind CSS v4 configuration. This skill ensures you get the modern CSS-first setup, not the deprecated v3 approach.

Purpose

IMPORTANT: shadcn/ui CLI and AI assistants often generate Tailwind v3 configs by default. This skill ensures:

• Tailwind v4 CSS-first configuration
• Proper @theme block with shadcn color tokens
• No deprecated tailwind.config.js files
• Correct dependency versions

When to Use

• Setting up a new Next.js project with shadcn/ui
• Adding shadcn/ui to an existing project
• Migrating from shadcn + Tailwind v3 to v4
• Resetting a broken shadcn configuration

Quick Start

# Full setup (recommended)
python3 scripts/setup.py --root .

# With specific theme
python3 scripts/setup.py --root . --theme zinc

# Install specific components
python3 scripts/setup.py --root . --components button,card,input,dialog

# Next.js App Router (default)
python3 scripts/setup.py --root . --app-router

# Next.js Pages Router
python3 scripts/setup.py --root . --pages-router

What Gets Installed

Dependencies

{
  "dependencies": {
    "class-variance-authority": "^0.7.0",
    "clsx": "^2.1.0",
    "tailwind-merge": "^2.2.0",
    "lucide-react": "^0.400.0"
  },
  "devDependencies": {
    "tailwindcss": "^4.0.0",
    "@tailwindcss/postcss": "^4.0.0"
  }
}

File Structure

project/
├── src/
│   ├── app/
│   │   └── globals.css           # Tailwind v4 + shadcn theme
│   ├── components/
│   │   └── ui/                   # shadcn components
│   │       ├── button.tsx
│   │       ├── card.tsx
│   │       └── ...
│   └── lib/
│       └── utils.ts              # cn() utility
├── components.json               # shadcn config
└── postcss.config.mjs            # PostCSS with @tailwindcss/postcss

Tailwind v4 + shadcn CSS Configuration

The skill generates a CSS-first configuration:

/* src/app/globals.css */
@import "tailwindcss";

@theme {
  /* Base colors */
  --color-background: hsl(0 0% 100%);
  --color-foreground: hsl(222.2 84% 4.9%);

  /* Card */
  --color-card: hsl(0 0% 100%);
  --color-card-foreground: hsl(222.2 84% 4.9%);

  /* Popover */
  --color-popover: hsl(0 0% 100%);
  --color-popover-foreground: hsl(222.2 84% 4.9%);

  /* Primary */
  --color-primary: hsl(222.2 47.4% 11.2%);
  --color-primary-foreground: hsl(210 40% 98%);

  /* Secondary */
  --color-secondary: hsl(210 40% 96.1%);
  --color-secondary-foreground: hsl(222.2 47.4% 11.2%);

  /* Muted */
  --color-muted: hsl(210 40% 96.1%);
  --color-muted-foreground: hsl(215.4 16.3% 46.9%);

  /* Accent */
  --color-accent: hsl(210 40% 96.1%);
  --color-accent-foreground: hsl(222.2 47.4% 11.2%);

  /* Destructive */
  --color-destructive: hsl(0 84.2% 60.2%);
  --color-destructive-foreground: hsl(210 40% 98%);

  /* Border & Input */
  --color-border: hsl(214.3 31.8% 91.4%);
  --color-input: hsl(214.3 31.8% 91.4%);
  --color-ring: hsl(222.2 84% 4.9%);

  /* Chart colors */
  --color-chart-1: hsl(12 76% 61%);
  --color-chart-2: hsl(173 58% 39%);
  --color-chart-3: hsl(197 37% 24%);
  --color-chart-4: hsl(43 74% 66%);
  --color-chart-5: hsl(27 87% 67%);

  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 9999px;

  /* Sidebar (if using sidebar component) */
  --color-sidebar: hsl(0 0% 98%);
  --color-sidebar-foreground: hsl(240 5.3% 26.1%);
  --color-sidebar-primary: hsl(240 5.9% 10%);
  --color-sidebar-primary-foreground: hsl(0 0% 98%);
  --color-sidebar-accent: hsl(240 4.8% 95.9%);
  --color-sidebar-accent-foreground: hsl(240 5.9% 10%);
  --color-sidebar-border: hsl(220 13% 91%);
  --color-sidebar-ring: hsl(217.2 91.2% 59.8%);
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  @theme {
    --color-background: hsl(222.2 84% 4.9%);
    --color-foreground: hsl(210 40% 98%);
    --color-card: hsl(222.2 84% 4.9%);
    --color-card-foreground: hsl(210 40% 98%);
    --color-popover: hsl(222.2 84% 4.9%);
    --color-popover-foreground: hsl(210 40% 98%);
    --color-primary: hsl(210 40% 98%);
    --color-primary-foreground: hsl(222.2 47.4% 11.2%);
    --color-secondary: hsl(217.2 32.6% 17.5%);
    --color-secondary-foreground: hsl(210 40% 98%);
    --color-muted: hsl(217.2 32.6% 17.5%);
    --color-muted-foreground: hsl(215 20.2% 65.1%);
    --color-accent: hsl(217.2 32.6% 17.5%);
    --color-accent-foreground: hsl(210 40% 98%);
    --color-destructive: hsl(0 62.8% 30.6%);
    --color-destructive-foreground: hsl(210 40% 98%);
    --color-border: hsl(217.2 32.6% 17.5%);
    --color-input: hsl(217.2 32.6% 17.5%);
    --color-ring: hsl(212.7 26.8% 83.9%);
    --color-sidebar: hsl(240 5.9% 10%);
    --color-sidebar-foreground: hsl(240 4.8% 95.9%);
    --color-sidebar-primary: hsl(224.3 76.3% 48%);
    --color-sidebar-primary-foreground: hsl(0 0% 100%);
    --color-sidebar-accent: hsl(240 3.7% 15.9%);
    --color-sidebar-accent-foreground: hsl(240 4.8% 95.9%);
    --color-sidebar-border: hsl(240 3.7% 15.9%);
  }
}

/* Base styles */
* {
  border-color: var(--color-border);
}

body {
  background-color: var(--color-background);
  color: var(--color-foreground);
}

Available Themes

Common Components

Install commonly used components:

# Essential set
python3 scripts/setup.py --root . \
  --components button,card,input,label,dialog,dropdown-menu,toast

# Form-focused
python3 scripts/setup.py --root . \
  --components form,input,label,select,checkbox,radio-group,switch,textarea

# Dashboard
python3 scripts/setup.py --root . \
  --components card,table,tabs,badge,avatar,dropdown-menu,sheet,sidebar

components.json Configuration

{
  "$schema": "https://ui.shadcn.com/schema.json",
  "style": "default",
  "rsc": true,
  "tsx": true,
  "tailwind": {
    "config": "",
    "css": "src/app/globals.css",
    "baseColor": "zinc",
    "cssVariables": true,
    "prefix": ""
  },
  "aliases": {
    "components": "@/components",
    "utils": "@/lib/utils",
    "ui": "@/components/ui",
    "lib": "@/lib",
    "hooks": "@/hooks"
  },
  "iconLibrary": "lucide"
}

Note: The tailwind.config is empty because we use CSS-first configuration in v4.

Utils File

// src/lib/utils.ts
import { clsx, type ClassValue } from 'clsx';
import { twMerge } from 'tailwind-merge';

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));
}

Usage After Setup

Adding Components

# Using bunx (recommended with bun)
bunx shadcn@latest add button

# Multiple components
bunx shadcn@latest add card dialog dropdown-menu

Using Components

import { Button } from '@/components/ui/button';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';

export function MyComponent() {
  return (
    <Card>
      <CardHeader>
        <CardTitle>Welcome</CardTitle>
      </CardHeader>
      <CardContent>
        <Button>Click me</Button>
      </CardContent>
    </Card>
  );
}

Dark Mode Support

The CSS uses prefers-color-scheme by default. For manual toggle:

// Add to layout.tsx or a theme provider
'use client';

import { useEffect, useState } from 'react';

export function ThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setTheme] = useState<'light' | 'dark'>('light');

  useEffect(() => {
    document.documentElement.classList.toggle('dark', theme === 'dark');
  }, [theme]);

  return (
    <ThemeContext.Provider value={{ theme, setTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}

Update CSS to use class-based dark mode:

/* Replace @media (prefers-color-scheme: dark) with: */
.dark {
  --color-background: hsl(222.2 84% 4.9%);
  /* ... rest of dark theme variables */
}

Troubleshooting

"tailwind.config.js created by shadcn CLI"

Delete it. The CLI sometimes generates v3 configs. Run:

rm tailwind.config.js tailwind.config.ts

Components not styled correctly

1. Check that globals.css is imported in your layout
2. Verify @import "tailwindcss" is at the top
3. Ensure @theme block contains all required variables

Type errors with components

Run:

bun add -D @types/react @types/react-dom

cn() utility not found

Create src/lib/utils.ts:

import { clsx, type ClassValue } from 'clsx';
import { twMerge } from 'tailwind-merge';

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));
}

Validation

After setup, run the Tailwind v4 validator:

python3 scripts/validate.py --root . --verbose

This ensures no v3 patterns were accidentally introduced.