Fix "Learn more" Button & Add Slide Navigation Button in index.html

[DiyaGhorpade]

Problems:
1.The "Learn more" button currently appears to be not redirecting properly.
2.There’s no clear button for users to move to the next slide.
3.UI enhancement in About Us section of index.html to match the green and white theme of the project.

Suggested Fixes:
1.Align and style the "Learn more" button properly with correct link functionality.
2.Add a "Next Slide" button beside existing buttons to smoothly navigate carousel slides.
3.Change the colour of the text in the About Us boxes to green and white.

[github-actions]

Thank you for raising this issue!

We'll review it as soon as possible. We truly appreciate your contributions! ✨

Meanwhile make sure you've visited the README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md before creating a PR for this. Also, please do NOT create a PR until this issue has been assigned to you. 😊

[DiyaGhorpade]

@gyanshankar1708 please check this issue and let me know.

[gyanshankar1708]

@DiyaGhorpade Assigned!!