fix: remove duplicated styles in index.css

[guilhermefogacadev]

📌 Description

Removed the duplicated stylesheet code in frontend/src/index.css. The file contained three copies of the entire stylesheet, which caused conflicts with the .hover-lift class and increased the CSS bundle size unnecessarily. I removed the duplicates and kept the correct, most updated copy.

🔗 Related Issue

Closes #1681

🛠 Changes Made

• Deleted the duplicated CSS code (lines 1 to 342) in frontend/src/index.css.
• Ensured the correct .hover-lift class (with translateY(-6px) scale(1.015)) is preserved and working smoothly.
• Maintained the smooth scroll behavior and footer variables from the final copy.

📸 Screenshots (if applicable)

N/A (Code cleanup / hover effect restored).

✅ Checklist

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

🚀 Notes for Reviewers

The GitHub Actions bot kept giving me a 6h cooldown loop when I tried to use /assign on the issue, so I went ahead and submitted the PR directly since the fix was straightforward. Ready for review!