Implement theme toggle functionality and refactor styles for light/dark mode support

src/contexts/ThemeContext.tsx

@@ -0,0 +1,68 @@
+import React, { createContext, useState, useEffect } from 'react'
+import type { ReactNode } from 'react'
+
+type Theme = 'light' | 'dark'
+
+interface ThemeContextType {
+  theme: Theme
+  toggleTheme: () => void
+}
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined)
+
+export { ThemeContext }
+
+interface ThemeProviderProps {
+  children: ReactNode
+}
+
+export const ThemeProvider: React.FC<ThemeProviderProps> = ({ children }) => {
+  // Get initial theme from localStorage or system preference
+  const getInitialTheme = (): Theme => {
+    const savedTheme = localStorage.getItem('theme') as Theme
+    if (savedTheme) {
+      return savedTheme
+    }
+    // Check system preference
+    return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
+  }
+
+  const [theme, setTheme] = useState<Theme>(getInitialTheme)
+
+  // Update document class and localStorage when theme changes
+  useEffect(() => {
+    const root = document.documentElement
+    root.classList.remove('light', 'dark')
+    root.classList.add(theme)
+    localStorage.setItem('theme', theme)
+  }, [theme])
+
+  // Listen for system theme changes
+  useEffect(() => {
+    const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)')
+    const handleChange = (e: MediaQueryListEvent) => {
+      // Only update if no manual preference is saved
+      if (!localStorage.getItem('theme')) {
+        setTheme(e.matches ? 'dark' : 'light')
+      }
+    }
+
+    mediaQuery.addEventListener('change', handleChange)
+    return () => mediaQuery.removeEventListener('change', handleChange)
+  }, [])
+
+  const toggleTheme = () => {
+    setTheme(prevTheme => prevTheme === 'light' ? 'dark' : 'light')
+  }
+
+  const value = {
+    theme,
+    toggleTheme
+  }
+
+  return (
+    <ThemeContext.Provider value={value}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}