chore: complete initial setup for Next.js project with TypeScript, Tailwind CSS, ESLint, and Prettier; remove unnecessary .DS_Store file

src/contexts/ThemeContext.tsx

@@ -0,0 +1,59 @@
+'use client';
+
+import { createContext, useContext, useEffect, useState, ReactNode, useCallback } from 'react';
+
+type Theme = 'light' | 'dark';
+
+interface ThemeContextType {
+  theme: Theme;
+  setTheme: (theme: Theme) => void;
+  toggleTheme: () => void;
+}
+
+const ThemeContext = createContext<ThemeContextType | null>(null);
+
+function getInitialTheme(): Theme {
+  if (typeof window === 'undefined') return 'light';
+
+  const stored = localStorage.getItem('theme') as Theme | null;
+  if (stored) return stored;
+
+  return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+}
+
+interface ThemeProviderProps {
+  children: ReactNode;
+}
+
+export function ThemeProvider({ children }: ThemeProviderProps) {
+  const [theme, setThemeState] = useState<Theme>(getInitialTheme);
+
+  useEffect(() => {
+    const root = document.documentElement;
+    root.classList.remove('light', 'dark');
+    root.classList.add(theme);
+    localStorage.setItem('theme', theme);
+  }, [theme]);
+
+  const setTheme = useCallback((newTheme: Theme) => {
+    setThemeState(newTheme);
+  }, []);
+
+  const toggleTheme = useCallback(() => {
+    setThemeState((prev) => (prev === 'light' ? 'dark' : 'light'));
+  }, []);
+
+  return (
+    <ThemeContext.Provider value={{ theme, setTheme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  );
+}
+
+export function useTheme() {
+  const context = useContext(ThemeContext);
+  if (context === null) {
+    throw new Error('useTheme must be used within a ThemeProvider');
+  }
+  return context;
+}