What is useContext and how does it solve prop drilling? useContext क्या है और prop drilling को कैसे solve करता है?

// Create context
const ThemeContext = React.createContext();

// Provider
function App() {
  const [theme, setTheme] = useState('light');
  
  return (
    <ThemeContext.Provider value={{ theme, setTheme }}>
      <Header />
      <Main />
    </ThemeContext.Provider>
  );
}

// Consumer
function DeepComponent() {
  const { theme, setTheme } = useContext(ThemeContext);
  
  return (
    <div style={{ background: theme === 'light' ? 'white' : 'black' }}>
      <button onClick={() => setTheme(theme === 'light' ? 'dark' : 'light')}>
        Toggle Theme
      </button>
    </div>
  );
}

// Multiple contexts
const UserContext = React.createContext();
const NotificationContext = React.createContext();