Update app.py

app.py

@@ -76,4 +76,22 @@ if submitted:
     st.text(result)
 
     # CSV export
-    csv_buffer = io.String_
+    csv_buffer = io.StringIO()
+    writer = csv.writer(csv_buffer)
+    writer.writerow(["Material", "Quantity"])
+
+    for line in result.splitlines():
+        if ":" in line:
+            parts = line.split(":", 1)
+            writer.writerow([parts[0].strip(), parts[1].strip()])
+
+    st.download_button(
+        label="📥 Download Estimate",
+        data=csv_buffer.getvalue(),
+        file_name="buildsmart_estimate.csv",
+        mime="text/csv"
+    )
+
+# Footer
+st.markdown("---")
+st.caption("Powered by Groq · Securely using Streamlit secrets")