Implement Dark Mode

[ABarpanda]

Implement a Dark Mode theme for the application to enhance user experience in low-light environments.

Requirements:

• Add a switch or toggle to enable/disable Dark Mode.
• Ensure all major UI components have styles for both light and dark themes.
• Persist user preference using local storage or similar approach.
• Test theme compatibility across browsers.

Acceptance Criteria:

• Users can easily switch between Light and Dark modes.
• All primary screens are visually consistent and readable in both modes.
• No loss of information or major UI element breaks in Dark Mode.

Label this issue as enhancement.