Fix hamburger menu background for better readability

[ARYANPATEL-BIT]

The hamburger menu currently has a transparent background, which makes the navigation links difficult to read against certain page content.

Steps to Fix :

1. Add a solid or semi-transparent background to the hamburger menu.

2. Verify that all nav links are clearly visible and accessible.

[ARYANPATEL-BIT]

@oathar

I'd like to work on this issue. I've already identified the root cause and have a working fix locally.

Could you please assign this issue to me? I'm ready to submit a PR once assigned.

Thank you!