Replace floating sidebar with hamburger menu navigation

- Remove floating sidebar navigation box from right side
- Replace Streamlit sidebar arrow with hamburger menu (☰) in top left
- Add CSS for styled hamburger menu with dropdown
- Include JavaScript for menu toggle functionality
- Menu contains: Improvements, Chatbot, and Start Over options
- Auto-close menu when clicking outside or selecting option
- Clean, modern navigation pattern following UX best practices

app/streamlit_app.py

@@ -625,36 +625,7 @@ def main():
         border-radius: 5px;
     }
     
-    .sidebar-nav {
-        position: fixed;
-        top: 100px;
-        right: 20px;
-        background: rgba(76, 175, 80, 0.05);
-        border: 2px solid rgba(76, 175, 80, 0.2);
-        border-radius: 15px;
-        padding: 15px;
-        z-index: 1000;
-        min-width: 150px;
-    }
-    
-    .nav-button {
-        display: block;
-        width: 100%;
-        margin: 5px 0;
-        padding: 8px 12px;
-        background: #0B3B0B;
-        color: white;
-        border: none;
-        border-radius: 20px;
-        text-align: center;
-        text-decoration: none;
-        font-size: 12px;
-        cursor: pointer;
-    }
-    
-    .nav-button:hover {
-        background: #4CAF50;
-    }
+
     
     .stButton > button {
         background-color: #0B3B0B;
@@ -715,42 +686,113 @@ def main():
     enable_gpt = any_service_available
     sample_rate = 1
 
-    # Floating sidebar navigation (appears after Step 3)
+    # Hamburger menu navigation (appears after Step 3)
     if st.session_state.current_step >= 3:
-        st.session_state.show_sidebar = True
-        
-    if st.session_state.show_sidebar:
+        # Add hamburger menu CSS and HTML
         st.markdown("""
-        <div class="sidebar-nav">
-            <h4 style="color: #0B3B0B; margin: 0 0 10px 0; font-size: 14px;">Navigation</h4>
+        <style>
+        .hamburger-menu {
+            position: fixed;
+            top: 20px;
+            left: 20px;
+            z-index: 1000;
+            background: #0B3B0B;
+            color: white;
+            border: none;
+            border-radius: 8px;
+            padding: 10px;
+            font-size: 18px;
+            cursor: pointer;
+            box-shadow: 0 2px 8px rgba(11, 59, 11, 0.3);
+        }
+        
+        .hamburger-menu:hover {
+            background: #4CAF50;
+        }
+        
+        .menu-content {
+            position: fixed;
+            top: 60px;
+            left: 20px;
+            background: rgba(255, 255, 255, 0.95);
+            border: 2px solid #4CAF50;
+            border-radius: 10px;
+            padding: 15px;
+            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+            z-index: 999;
+            min-width: 180px;
+            backdrop-filter: blur(10px);
+        }
+        
+        .menu-hidden {
+            display: none;
+        }
+        </style>
+        
+        <div class="hamburger-menu" onclick="toggleMenu()">
+            ☰
+        </div>
+        
+        <div id="menu-content" class="menu-content menu-hidden">
+            <h4 style="color: #0B3B0B; margin: 0 0 10px 0;">Navigation</h4>
         </div>
+        
+        <script>
+        function toggleMenu() {
+            const menu = document.getElementById('menu-content');
+            menu.classList.toggle('menu-hidden');
+        }
+        
+        // Close menu when clicking outside
+        document.addEventListener('click', function(event) {
+            const menu = document.getElementById('menu-content');
+            const hamburger = document.querySelector('.hamburger-menu');
+            if (!menu.contains(event.target) && !hamburger.contains(event.target)) {
+                menu.classList.add('menu-hidden');
+            }
+        });
+        </script>
         """, unsafe_allow_html=True)
         
-        # Navigation buttons in sidebar
-        sidebar_col = st.sidebar
-        with sidebar_col:
-            st.markdown("### 🧭 Quick Navigation")
+        # Navigation menu in main content (only show when menu should be visible)
+        if 'show_menu' not in st.session_state:
+            st.session_state.show_menu = False
             
-            if st.button("⚙️ Options", key="nav_options", use_container_width=True):
-                st.session_state.current_step = 3
+        # Menu toggle button
+        col1, col2, col3 = st.columns([1, 8, 1])
+        with col1:
+            if st.button("☰", key="menu_toggle", help="Navigation Menu"):
+                st.session_state.show_menu = not st.session_state.show_menu
                 st.rerun()
+        
+        # Show menu content if toggled
+        if st.session_state.show_menu:
+            with st.container():
+                st.markdown("#### 🧭 Navigation")
                 
-            if st.button("🎯 Improvements", key="nav_improvements", use_container_width=True):
-                st.session_state.current_step = 4
-                st.rerun()
+                nav_col1, nav_col2 = st.columns(2)
                 
-            if st.button("💬 Chatbot", key="nav_chatbot", use_container_width=True):
-                st.session_state.current_step = 5
-                st.rerun()
+                with nav_col1:
+                    if st.button("🎯 Improvements", key="nav_improvements", use_container_width=True):
+                        st.session_state.current_step = 4
+                        st.session_state.show_menu = False
+                        st.rerun()
+                        
+                with nav_col2:
+                    if st.button("💬 Chatbot", key="nav_chatbot", use_container_width=True):
+                        st.session_state.current_step = 5
+                        st.session_state.show_menu = False
+                        st.rerun()
                 
-            st.markdown("---")
-            if st.button("🔄 Start Over", key="nav_start_over", use_container_width=True):
-                # Reset all session state
-                for key in list(st.session_state.keys()):
-                    if key != 'session_initialized':
-                        del st.session_state[key]
-                st.session_state.current_step = 1
-                st.rerun()
+                if st.button("🔄 Start Over", key="nav_start_over", use_container_width=True):
+                    # Reset all session state
+                    for key in list(st.session_state.keys()):
+                        if key != 'session_initialized':
+                            del st.session_state[key]
+                    st.session_state.current_step = 1
+                    st.rerun()
+                
+                st.markdown("---")
 
     # Step-based content rendering
     if st.session_state.current_step == 1: