app.py

import streamlit as st

# Page settings
st.set_page_config(page_title="BMI Calculator", layout="centered")

st.title("💪 BMI Calculator")
st.subheader("Check your Body Mass Index")

# Input fields
height = st.number_input("Enter your height (in cm):", min_value=50, max_value=250, step=1)
weight = st.number_input("Enter your weight (in kg):", min_value=10, max_value=300, step=1)

# BMI calculation
if st.button("Calculate BMI"):
    if height == 0:
        st.error("Height must be greater than 0.")
    else:
        height_m = height / 100  # Convert to meters
        bmi = weight / (height_m ** 2)
        st.success(f"Your BMI is: **{bmi:.2f}**")

        # BMI category
        if bmi < 18.5:
            st.info("💡 You are **Underweight**.")
        elif 18.5 <= bmi < 24.9:
            st.success("✅ You have a **Normal** weight.")
        elif 25 <= bmi < 29.9:
            st.warning("⚠️ You are **Overweight**.")
        else:
            st.error("❌ You are **Obese**.")