style: fix navbar text contrast and hover visibility in dark mode

[Nishant-Babariya-21]

📌 Description

Fixed a UI contrast issue in the main navigation bar. When users switched to dark mode, the links had low visibility, and hovering over inactive links made the text wash out and blend into the changing background.

🔗 Related Issue

Closes #860

🛠 Changes Made

• Added missing dark: Tailwind CSS class modifiers to the active and idle NavLink items inside Navbar.jsx.
• Set explicit dark-mode backgrounds and hover text properties (dark:hover:text-white) so unselected items stay clearly legible.
• Synchronized styling changes across both desktop row rendering and mobile menu drawer maps to keep layout breakpoints uniform.

📸 Screenshots (if applicable)

✅ Checklist

• Code runs locally
• Followed project structure
• No console errors
• Properly tested changes
• Linked the issue

🚀 Notes for Reviewers

Tested on local dev server (localhost:5173) across multiple screen sizes and verified that transitions work smoothly when toggling between light and dark modes.

[Nishant-Babariya-21]

@aryandas2911 plz check this pr,and if there is any issue give follow up comments