app.py

import streamlit as st

# ✅ Must be the first command
st.set_page_config(page_title="TransPolymer", layout="wide", page_icon="🧪")

# ✅ Import your page modules
import home
import prediction
import about
import contact

# ✅ Navigation Sidebar
st.sidebar.title("🔗 Navigation")
page = st.sidebar.radio("Select a Page", ["Home", "Predictions", "About", "Contact"])

# ✅ Optional: Override via URL (?page=Contact)
query_params = st.query_params
if "page" in query_params:
    param_page = query_params["page"][0].capitalize()
    if param_page in ["Home", "Predictions", "About", "Contact"]:
        page = param_page

# ✅ Page loading logic
def load_page(page_name):
    if page_name == "Home":
        home.show()
    elif page_name == "Predictions":
        prediction.show()
    elif page_name == "About":
        about.show()
    elif page_name == "Contact":
        contact.show()
    else:
        st.error("Page not found.")

# ✅ Load the selected page
load_page(page)