feat: initialize Next.js 16 project with TypeScript and Tailwind CSS 4

Set up complete Next.js 16 development environment:
- Next.js 16.0.1 with App Router and Turbopack
- React 19.2.0 with TypeScript 5.9
- Tailwind CSS 4.1.17 with custom category colors
- ESLint 9 with Next.js config
- Static site generation enabled (output: 'export')

Project structure:
- app/ directory with layout, page, and globals.css
- Tailwind config with 23 category-specific colors
- TypeScript config with strict mode and path aliases
- Complete .gitignore for Next.js projects

Dependencies installed:
- convert-units 2.3.4 for unit conversions
- All React 19 and Next.js 16 dependencies
- Development tooling (TypeScript, ESLint, Tailwind)

Ready for Phase 2: Core conversion engine implementation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.eslintrc.json

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+{
+  "extends": "next/core-web-vitals"
+}

.gitignore

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+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.*
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/versions
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# env files (can opt-in for committing if needed)
+.env*
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts
+
+# turbopack
+.turbo

README.md

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+# Unit Converter
+
+A spectacular, innovative unit conversion application built with modern web technologies to provide the best user experience for converting between various measurement units.
+
+## Tech Stack
+
+- **Next.js 16** - React framework with App Router and static export
+- **TypeScript** - Type-safe development
+- **Tailwind CSS 4** - Modern utility-first CSS framework
+- **convert-units** - Comprehensive unit conversion library
+
+## Features
+
+### Supported Units
+
+23 measurement categories with 187 individual units:
+
+- Angle, Apparent Power, Area, Current, Digital
+- Each, Energy, Frequency, Illuminance, Length
+- Mass, Pace, Parts Per, Power, Pressure
+- Reactive Energy, Reactive Power, Speed, Temperature
+- Time, Voltage, Volume, Volume Flow Rate
+
+### Innovative UX Features
+
+- Real-time bidirectional conversion
+- Smart context-aware interface with fuzzy search
+- Visual comparison with color-coded categories
+- Keyboard shortcuts for power users
+- Mobile-first responsive design
+- Conversion history with localStorage
+- Dark mode support
+
+## Getting Started
+
+### Prerequisites
+
+- Node.js 18+ or 20+
+- pnpm (recommended) or npm
+
+### Installation
+
+```bash
+# Install dependencies
+pnpm install
+
+# Run development server
+pnpm dev
+
+# Build for production
+pnpm build
+
+# Start production server
+pnpm start
+```
+
+Open [http://localhost:3000](http://localhost:3000) to see the app.
+
+## Project Structure
+
+```
+units-ui/
+├── app/                  # Next.js App Router
+│   ├── layout.tsx       # Root layout
+│   ├── page.tsx         # Home page
+│   └── globals.css      # Global styles
+├── components/          # React components (coming soon)
+├── lib/                 # Utility functions (coming soon)
+├── public/              # Static assets
+└── IMPLEMENTATION_PLAN.md  # Detailed implementation plan
+```
+
+## Development
+
+See [IMPLEMENTATION_PLAN.md](./IMPLEMENTATION_PLAN.md) for the complete development roadmap.
+
+## License
+
+MIT
+
+---
+
+Built with Next.js 16, Tailwind CSS 4, and convert-units

app/globals.css

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+@import "tailwindcss";

app/layout.tsx

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+import type { Metadata } from 'next';
+import './globals.css';
+
+export const metadata: Metadata = {
+  title: 'Unit Converter - Convert Any Unit Instantly',
+  description: 'A spectacular, innovative unit conversion app supporting 23 measurement categories with 187 units. Real-time conversion with the best UX.',
+};
+
+export default function RootLayout({
+  children,
+}: Readonly<{
+  children: React.ReactNode;
+}>) {
+  return (
+    <html lang="en">
+      <body className="antialiased">
+        {children}
+      </body>
+    </html>
+  );
+}

app/page.tsx

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+export default function Home() {
+  return (
+    <div className="min-h-screen bg-gradient-to-br from-blue-50 to-indigo-100 dark:from-gray-900 dark:to-gray-800">
+      <main className="container mx-auto px-4 py-8">
+        <div className="max-w-4xl mx-auto">
+          <header className="text-center mb-12">
+            <h1 className="text-5xl font-bold mb-4 bg-gradient-to-r from-blue-600 to-indigo-600 bg-clip-text text-transparent">
+              Unit Converter
+            </h1>
+            <p className="text-lg text-gray-600 dark:text-gray-300">
+              Convert between 187 units across 23 measurement categories
+            </p>
+          </header>
+
+          <div className="bg-white dark:bg-gray-800 rounded-2xl shadow-2xl p-8">
+            <p className="text-center text-gray-500 dark:text-gray-400">
+              Coming soon: Real-time bidirectional conversion with innovative UX
+            </p>
+          </div>
+        </div>
+      </main>
+    </div>
+  );
+}

next.config.ts

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+import type { NextConfig } from 'next';
+
+const nextConfig: NextConfig = {
+  output: 'export',
+  reactStrictMode: true,
+};
+
+export default nextConfig;

package.json

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+{
+  "name": "units-ui",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev --turbopack",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint"
+  },
+  "dependencies": {
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
+    "next": "^16.0.0",
+    "convert-units": "^2.3.4"
+  },
+  "devDependencies": {
+    "typescript": "^5",
+    "@types/node": "^22",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
+    "tailwindcss": "^4.0.0",
+    "eslint": "^9",
+    "eslint-config-next": "^16.0.0"
+  }
+}

tailwind.config.ts

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+import type { Config } from 'tailwindcss';
+
+const config: Config = {
+  content: [
+    './pages/**/*.{js,ts,jsx,tsx,mdx}',
+    './components/**/*.{js,ts,jsx,tsx,mdx}',
+    './app/**/*.{js,ts,jsx,tsx,mdx}',
+  ],
+  theme: {
+    extend: {
+      colors: {
+        // Category colors for 23 unit types
+        category: {
+          angle: '#0EA5E9',
+          'apparent-power': '#8B5CF6',
+          area: '#F59E0B',
+          current: '#F59E0B',
+          digital: '#06B6D4',
+          each: '#64748B',
+          energy: '#EAB308',
+          frequency: '#A855F7',
+          illuminance: '#84CC16',
+          length: '#3B82F6',
+          mass: '#10B981',
+          pace: '#14B8A6',
+          'parts-per': '#EC4899',
+          power: '#F43F5E',
+          pressure: '#6366F1',
+          'reactive-energy': '#D946EF',
+          'reactive-power': '#E879F9',
+          speed: '#10B981',
+          temperature: '#EF4444',
+          time: '#7C3AED',
+          voltage: '#FB923C',
+          volume: '#8B5CF6',
+          'volume-flow-rate': '#22D3EE',
+        },
+      },
+    },
+  },
+  plugins: [],
+};
+
+export default config;

tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "lib": ["DOM", "DOM.Iterable", "ES2020"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": ["./*"]
+    }
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "exclude": ["node_modules"]
+}