Implement a custom 404 error page that matches the current theme and design of the Openln-Engine site. The 404 page should provide a user-friendly message, keep users within the site experience, and offer navigation options (e.g., a link back to the homepage or main sections).

Requirements:

• Design the 404 page to visually align with the existing site theme (colors, fonts, layout).
• Add a helpful message indicating the page was not found.
• Include navigation options to guide users back to the main content.
• Ensure the 404 page is responsive and accessible.

This will improve user experience and maintain consistency across the platform.