box shadow when the hamburger menu in mobile design is open

[Akshaybagai52]

Reason/Context

We need this improvement for better user experience

Description

go to this url :-https://json-schema.org/ and turn on mobile responsive
then you can see there is drop shadow on navbar when it is not open so it is looking good

but when the navbar is open on clicking of hamburger menu then the box shadow removed and it is merging with the white background of the content as can be seen in the screenshot

so there is no separation between navbar and content.

Do you think this work might require an Architectural Decision Record (ADR)? (significant or noteworthy)

Yes/No
[JUSTIFICATION]

I would love to work on this issue

[DhairyaMajmudar]

@benjagm shall I incorporate this small change in my existing PR #359

Screenshot after changes

[benjagm]

thanks @Akshaybagai52 for finding this!