style: improve color contrast and landing page UI

[Mohitswamii]

Summary

Improved landing page visual appearance and accessibility.

Closes #1497

Changes Made

• Enhanced text contrast for better readability
• Improved muted text colors
• Added hover effects to dashboard cards
• Refined landing page styling consistency
• Improved overall UI accessibility

Type of Change

• UI Improvement
• Accessibility Improvement
• Bug Fix
• Documentation

Testing

• Tested locally
• No console errors
• Responsive design checked

[vercel]

@Mohitswamii is attempting to deploy a commit to the PRIYANSHU DOSHI's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

This PR has merge conflicts with main. Please rebase your branch against the latest main and force-push to resolve. Run: git fetch upstream && git rebase upstream/main