with col_export:
        if st.session_state.history:
            # Prepare conversation text for export
            export_text = ""
            for idx, qa in enumerate(st.session_state.history, start=1):
                export_text += f"Q{idx}: {qa['question']}\n"
                export_text += f"A{idx}: {qa['answer']}\n\n"

            bio = io.BytesIO()
            bio.write(export_text.encode("utf-8"))
            bio.seek(0)

            st.download_button(
                label="📥 Export Chat History",
                data=bio,
                file_name="AI_Teaching_Assistant_Conversation.txt",
                mime="text/plain",
            )

    # User input
    user_input = st.text_input("Enter your question here:")

    if st.button("Ask"):
        if user_input.strip():
            with st.spinner("Generating AI response..."):
                response = generate_response(user_input.strip())
            st.session_state.history.append({"question": user_input.strip(), "answer": response})
        else:
            st.warning("⚠️ Please enter a question before clicking Ask.")

    # Display conversation history in scrollable container
    st.markdown("### Conversation History")
    st.markdown(
        """
        <style>
        .history-box {
            max-height: 400px;
            overflow-y: auto;
            border: 1px solid #ddd;
            padding: 12px;
            background-color: #f9f9f9;
            border-radius: 6px;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .question {
            font-weight: 600;
            color: #0a6ebd;
            margin-top: 12px;
            margin-bottom: 4px;
        }
        .answer {
            margin-bottom: 16px;
            white-space: pre-wrap;
            color: #333;
        }
        </style>
        """,
        unsafe_allow_html=True,
    )

    history_html = '<div class="history-box">'
    for idx, qa in enumerate(st.session_state.history, start=1):
        q = qa["question"]
        a = qa["answer"]
        history_html += f'<div class="question">Q{idx}: {q}</div>'
        history_html += f'<div class="answer">A{idx}: {a}</div>'
    history_html += '</div>'
    st.markdown(history_html, unsafe_allow_html=True)

def main():
    setup_ui()

if __name__ == "__main__":
    main()