Add Dark Mode Support to Website

[DeshDeepakKant]

Description:

The website currently lacks support for dark mode. To improve user experience and accessibility, dark mode should be implemented. This feature will allow users to toggle between light and dark themes, providing a more comfortable viewing experience, especially in low-light environments.

Required Updates:

1. Toggle for Dark Mode: Allow users to switch between light and dark themes.
2. Auto Theme Detection: Detect and apply dark or light mode based on the user’s system preferences.
3. Style Adjustments: Ensure proper styling for both modes.
4. Persistence: Save user preferences across sessions.