There is no index.html

[quincynyan]

Without that, README.md becomes the default webpage and not calculator.html

[quincynyan]

This pull request adds a new index.html file that serves as a container for displaying the calculator interface. The main change is the inclusion of an iframe that loads the calculator.html page, ensuring the calculator is shown full-screen.

• New HTML container:
  • Added index.html with an iframe that loads calculator.html and applies full viewport styling for seamless display.

Please accept PR

[quincynyan]

#1 needs reviewers