Add Background Color to Footer Section

The footer section currently has the same plain white background as the rest of the page, causing it to visually blend with the main content. This makes the footer less distinguish

<img width="1600" height="559" alt="Image" src="https://github.com/user-attachments/assets/590c86b7-1020-4e04-a1be-402e8486b8dd" />

Please assign me this issue with appropriate level and gssoc 2025 label.