PraveenMp/Stock ? reverse-engineered prompt

Build me a simple web page for calculating stock average for the Indian stock market.

I want to be able to add one or more buy entries, enter the quantity and buy price for each one, and instantly see the average price, total quantity, and total amount invested. Keep it very easy to use on mobile and desktop, with a clean layout and a clear button to reset everything.

If it makes sense, include quick formatting for Indian rupees and make the result update right away when I type. Please keep it as a single page that works in the browser, and make the design neat and modern but simple. If you need to check anything current, look up the latest docs online.