Commit working version with chunk state management, sonnet 4 and well made markdown chat

backend/app.py

@@ -203,7 +203,8 @@ async def chat_endpoint(request: ChatRequest):
     *   **Language:** The entire conversation must be in English, as indicated by the user's goal.
     *   **Focus:** Always prioritize intuitive, conceptual, and experimental understanding over formal, mathematical details.
     *   **Pacing:** The flow is dictated by the user's successful answers. Move from one question to the next smoothly.
-    
+    *   **Structure:** Importantly, maintain a clear and logical flow in the conversation. Never loose track of the objective.
+    *   **Markdown:** Output markdown if you think it is useful. Break your response into reasonable sections.
     Begin the conversation.
     """
 
@@ -230,13 +231,17 @@ async def chat_endpoint(request: ChatRequest):
 
         print("🤖 Calling Claude for chat response...")
         response = client.messages.create(
-            model="claude-3-5-sonnet-20241022",
-            max_tokens=1000,
+            model="claude-sonnet-4-20250514",
+            max_tokens=10000,
             system=system_prompt,  # system prompt here
-            messages=anthropic_messages
+            messages=anthropic_messages,
+            thinking={
+                "type": "enabled",
+                "budget_tokens": 5000
+            },
         )
 
-        response_text = response.content[0].text
+        response_text = response.content[1].text
         print(f"✅ Received response from Claude: {response_text[:100]}...")
         return {"role": "assistant", "content": response_text}
 

frontend/src/components/ChunkNavigation.jsx

@@ -22,10 +22,17 @@ const ChunkNavigation = ({
                     <div
                         key={index}
                         className={`w-3 h-3 rounded-full ${
-                            chunkStates[index] === 'understood' ? 'bg-green-500' :
-                            chunkStates[index] === 'skipped' ? 'bg-red-500' :
-                            chunkStates[index] === 'interactive' ? 'bg-blue-500' :
-                            index === currentChunkIndex ? 'bg-gray-600' : 'bg-gray-300'
+                            index === currentChunkIndex ? (
+                                chunkStates[index] === 'understood' ? 'bg-green-700' :
+                                chunkStates[index] === 'skipped' ? 'bg-red-700' :
+                                chunkStates[index] === 'interactive' ? 'bg-blue-700' :
+                                'bg-gray-600'
+                            ) : (
+                                chunkStates[index] === 'understood' ? 'bg-green-500' :
+                                chunkStates[index] === 'skipped' ? 'bg-red-500' :
+                                chunkStates[index] === 'interactive' ? 'bg-blue-500' :
+                                'bg-gray-300'
+                            )
                         }`}
                     />
                 ))}

frontend/src/components/ChunkPanel.jsx

@@ -154,7 +154,11 @@ const ChunkPanel = ({
                         <div className="flex items-center justify-center gap-4 mt-4 pt-4 border-gray-200">
                             <button 
                                 onClick={skipChunk}
-                                className="py-2 px-4 bg-white hover:bg-gray-50 border border-gray-300 rounded-lg transition-all text-sm"
+                                className={`py-2 px-4 border rounded-lg transition-all text-sm ${
+                                    chunkStates[currentChunkIndex] === 'skipped'
+                                        ? 'bg-red-500 text-white border-red-500 hover:bg-red-600'
+                                        : 'bg-white hover:bg-gray-50 border-gray-300'
+                                }`}
                             >
                                 Skip
                             </button>
@@ -173,7 +177,11 @@ const ChunkPanel = ({
                             </button>
                             <button 
                                 onClick={markChunkUnderstood}
-                                className="py-2 px-4 bg-white hover:bg-gray-50 border border-gray-300 rounded-lg transition-all text-sm"
+                                className={`py-2 px-4 border rounded-lg transition-all text-sm ${
+                                    chunkStates[currentChunkIndex] === 'understood'
+                                        ? 'bg-green-500 text-white border-green-500 hover:bg-green-600'
+                                        : 'bg-white hover:bg-gray-50 border-gray-300'
+                                }`}
                             >
                                 Understood
                             </button>
@@ -186,7 +194,11 @@ const ChunkPanel = ({
                     <div className="flex items-center justify-center gap-4 mt-4 pt-4 border-t border-gray-200">
                         <button 
                             onClick={skipChunk}
-                            className="py-2 px-4 bg-white hover:bg-gray-50 border border-gray-300 rounded-lg transition-all text-sm"
+                            className={`py-2 px-4 border rounded-lg transition-all text-sm ${
+                                chunkStates[currentChunkIndex] === 'skipped'
+                                    ? 'bg-red-500 text-white border-red-500 hover:bg-red-600'
+                                    : 'bg-white hover:bg-gray-50 border-gray-300'
+                            }`}
                         >
                             Skip
                         </button>
@@ -205,7 +217,11 @@ const ChunkPanel = ({
                         </button>
                         <button 
                             onClick={markChunkUnderstood}
-                            className="py-2 px-4 bg-white hover:bg-gray-50 border border-gray-300 rounded-lg transition-all text-sm"
+                            className={`py-2 px-4 border rounded-lg transition-all text-sm ${
+                                chunkStates[currentChunkIndex] === 'understood'
+                                    ? 'bg-green-500 text-white border-green-500 hover:bg-green-600'
+                                    : 'bg-white hover:bg-gray-50 border-gray-300'
+                            }`}
                         >
                             Understood
                         </button>

frontend/src/components/SimpleChat.jsx

@@ -1,4 +1,10 @@
 import { useState } from 'react';
+import ReactMarkdown from 'react-markdown';
+import remarkMath from 'remark-math';
+import rehypeKatex from 'rehype-katex';
+import rehypeRaw from 'rehype-raw';
+import { getChatMarkdownComponents } from '../utils/markdownComponents.jsx';
+
 
 const SimpleChat = ({ messages, onSend, isLoading }) => {
   const [input, setInput] = useState('');
@@ -20,13 +26,19 @@ const SimpleChat = ({ messages, onSend, isLoading }) => {
             className={`flex ${message.role === 'user' ? 'justify-end' : 'justify-start'}`}
           >
             <div
-              className={`max-w-[70%] p-3 rounded-lg ${
+              className={`max-w-[90%] p-3 rounded-lg ${
                 message.role === 'user'
-                  ? 'bg-blue-500 text-white'
-                  : 'bg-gray-100 text-gray-900'
+                  ? 'bg-gray-100 text-white'
+                  : 'bg-white text-gray-900'
               }`}
             >
-              {message.content}
+              <ReactMarkdown
+                  remarkPlugins={[remarkMath]}
+                  rehypePlugins={[rehypeRaw, rehypeKatex]}
+                  components={getChatMarkdownComponents()}
+                >
+                  {message.content}
+                </ReactMarkdown>
             </div>
           </div>
         ))}

frontend/src/hooks/useChunkNavigation.js

@@ -30,17 +30,51 @@ export const useChunkNavigation = (documentData, clearTypingAnimation) => {
     };
 
     const skipChunk = () => {
-        setChunkStates(prev => ({
-            ...prev,
-            [currentChunkIndex]: 'skipped'
-        }));
+        setChunkStates(prev => {
+            const currentState = prev[currentChunkIndex];
+            const newState = currentState === 'skipped' ? undefined : 'skipped';
+            
+            // Auto-advance to next chunk if setting to skipped (not toggling off)
+            if (newState === 'skipped' && documentData && currentChunkIndex < documentData.chunks.length - 1) {
+                setTimeout(() => {
+                    if (clearTypingAnimation) {
+                        clearTypingAnimation();
+                    }
+                    setCurrentChunkIndex(currentChunkIndex + 1);
+                    setChunkExpanded(true);
+                    setShowChat(false);
+                }, 100); // Small delay to allow state update to complete
+            }
+            
+            return {
+                ...prev,
+                [currentChunkIndex]: newState
+            };
+        });
     };
 
     const markChunkUnderstood = () => {
-        setChunkStates(prev => ({
-            ...prev,
-            [currentChunkIndex]: 'understood'
-        }));
+        setChunkStates(prev => {
+            const currentState = prev[currentChunkIndex];
+            const newState = currentState === 'understood' ? undefined : 'understood';
+            
+            // Auto-advance to next chunk if setting to understood (not toggling off)
+            if (newState === 'understood' && documentData && currentChunkIndex < documentData.chunks.length - 1) {
+                setTimeout(() => {
+                    if (clearTypingAnimation) {
+                        clearTypingAnimation();
+                    }
+                    setCurrentChunkIndex(currentChunkIndex + 1);
+                    setChunkExpanded(true);
+                    setShowChat(false);
+                }, 100); // Small delay to allow state update to complete
+            }
+            
+            return {
+                ...prev,
+                [currentChunkIndex]: newState
+            };
+        });
     };
 
     const startInteractiveLesson = (startChunkLessonFn) => {