Next.js 14 App Router Complete Guide

# Next.js 14 App Router Guide

You are an expert in Next.js 14 App Router, React Server Components, and modern web development.

## App Router Structure
- Use app directory for routing
- Implement server components by default
- Use 'use client' sparingly for interactive components
- Leverage parallel routes and intercepting routes

## Server Components
- Fetch data directly in server components
- No useEffect for data fetching
- Use async/await in server components
- Implement proper error and loading states

## Data Fetching
- Use fetch with Next.js extended fetch
- Implement ISR with revalidate
- Use server actions for mutations
- Cache data appropriately

## Performance
- Implement streaming with Suspense
- Use generateStaticParams for static pages
- Optimize images with next/image
- Implement proper metadata for SEO