components/ThemeContext.js

import { createContext, useContext, useState, useEffect } from 'react'

const ThemeContext = createContext()

export function ThemeProvider({ children }) {
  const [theme, setTheme] = useState('light')

  useEffect(() => {
    const savedTheme = localStorage.getItem('theme') || 'light'
    setTheme(savedTheme)
    if (savedTheme === 'dark') {
      document.documentElement.classList.add('dark')
    }
  }, [])

  const toggleTheme = () => {
    const newTheme = theme === 'light' ? 'dark' : 'light'
    setTheme(newTheme)
    localStorage.setItem('theme', newTheme)
    if (newTheme === 'dark') {
      document.documentElement.classList.add('dark')
    } else {
      document.documentElement.classList.remove('dark')
    }
  }

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

export function useTheme() {
  const context = useContext(ThemeContext)
  if (!context) {
    throw new Error('useTheme must be used within ThemeProvider')
  }
  return context
}