fix: Fixed Overline in NavBar

[sau-mili]

Title and Issue number

Title :

Issue No. : #1136

Code Stack : HTML CSS

Close #1136

Description

• Fixed the overline issue on navbar
• Removed other CSS bugs and index.html bugs

Video/Screenshots (mandatory)

Type of PR

• Bug fix
• Feature enhancement
• Documentation update
• Other (specify): _______________

Checklist:

• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested the changes thoroughly before submitting this pull request.
• I have provided relevant issue numbers, screenshots, and videos after making the changes.
• I have gone through the contributing.md file before contributing

Additional context:

##Are you contributing under any Open-source programme?

• I am contributing under GSSOC'24
• I am contributing under VSOC'24

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[apu52]

@sau-mili good work