Improve UI accessibility and visual consistency

[Mitali-kumari905]

Summary

This PR introduces several UI and accessibility improvements across the Climate Shield homepage.

Changes Made

• Fixed margin/alignment issues for improved layout consistency.
• Improved navigation link colors in light mode to ensure sufficient contrast and readability.
• Added title attributes to icons so their purpose is clear when hovered.
• Added smooth transition and hover effects to cards for a better user experience.
• Enhanced overall visual consistency across light and dark themes.

Impact

• Better accessibility and usability in light mode.
• Improved user feedback through hover interactions.
• Easier navigation and understanding of icon actions.
• More polished and responsive UI experience.

[Mitali-kumari905]

please respond