426: updated the navbar fixing the stated bgs

[Manasi200609]

Description

This PR fixes the issue where section headings were hidden behind the fixed navbar
when navigating using navbar links.

Changes Made

• Added scroll offset so headings appear below the navbar
• Improved navigation and readability

Related Issue

Fixes #426

Type of Change

• 🐛 Bug Fix — Fixes a documented issue or incorrect behavior
• ✨ Content Enhancement — Updates or improves existing content
• ✍️ New Content — Adds new chapters, examples, or significant sections
• 🛠️ Other — Please describe in the Description of Changes section

Additional Notes (Optional)

Checklist

• I have searched open pull requests to avoid duplicates.
• I have built the book locally using the build instructions and verified my changes work as expected.
• I have written clear, conventional commit messages.
  Note: This change is CSS-only and does not affect build configuration.

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[dineshkolhe1]

Hello @Manasi200609 👋

I hope you’re doing well. I’m currently exploring the organization and working on understanding the codebase. I wanted to ask for your guidance on the best way to proceed.

[Manasi200609]

Hello @dineshkolhe1 👋
Thanks for reaching out. I’m currently working on this PR and exploring the codebase as well. I’ll update the PR if there are any changes or insights as I proceed. Appreciate your message!