shaharia-islam-png/BMI-Calculator ? reverse-engineered prompt

Build me a simple BMI calculator app where someone can enter their height and weight, then instantly see their BMI and what category they fall into, like underweight, normal, overweight, or obese.

I want it to feel clean and easy to use, with a simple form, a clear result area, and some basic guidance explaining what the number means. If it helps, add a button to calculate and another to clear the form. Make it work nicely on both desktop and phone screens, and keep the design modern but minimal.

If you need to check current best practices or look up anything online while building it, go ahead. Just make sure the final result is a polished app that is easy for a regular person to understand and use right away.