Prepare dark theme, add pricing page

lib/theme-context.tsx

@@ -0,0 +1,49 @@
+"use client";
+import React, { createContext, useState, useEffect, ReactNode, useContext } from 'react';
+
+type Theme = 'light' | 'dark';
+
+interface ThemeContextType {
+  theme: Theme;
+  toggleTheme: () => void;
+}
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined);
+
+export const ThemeProvider: React.FC<{ children: ReactNode }> = ({ children }) => {
+  const [theme, setTheme] = useState<Theme>('dark'); // Default to dark mode
+
+  useEffect(() => {
+    const savedTheme = localStorage.getItem('theme') as Theme | null;
+    if (savedTheme) {
+      setTheme(savedTheme);
+    }
+  }, []);
+
+  useEffect(() => {
+    if (theme === 'dark') {
+      document.documentElement.classList.add('dark');
+    } else {
+      document.documentElement.classList.remove('dark');
+    }
+    localStorage.setItem('theme', theme);
+  }, [theme]);
+
+  const toggleTheme = () => {
+    setTheme((prevTheme) => (prevTheme === 'dark' ? 'light' : 'dark'));
+  };
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  );
+};
+
+export const useTheme = (): ThemeContextType => {
+  const context = useContext(ThemeContext);
+  if (context === undefined) {
+    throw new Error('useTheme must be used within a ThemeProvider');
+  }
+  return context;
+};