Fixed: Issue#501 Improve Navbar and Space below Navbar

[ayushsachan123]

Description

Improve Navbar and Space below Navbar

Updated bootstrap class for css. Add Script for responsive behaviour of navbar

Fixes #(501)

Screenshots

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Checklist

• [x] Tests have been added or updated to cover the changes
• [x] Documentation has been updated to reflect the changes
• [x] Code follows the established coding style guidelines
• [x] All tests are passing

[ayushsachan123]

PTAL Please Add this PR under GSSOC'23