diff --git a/backend/CLAUDE.md b/backend/CLAUDE.md
new file mode 100644
index 0000000..124ed9c
--- /dev/null
+++ b/backend/CLAUDE.md
@@ -0,0 +1,134 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Common Development Commands
+
+### Running the Application
+```bash
+npm run dev    # Development mode with nodemon hot reload
+npm start      # Production mode
+```
+
+### Docker Commands
+```bash
+# Production deployment
+docker-compose up -d
+
+# Development with hot reload
+docker-compose --profile dev up fizika-admin-dev
+
+# Build image manually
+docker build -t fizika-admin ./backend
+```
+
+### Environment Setup
+```bash
+cp .env.example .env
+# Edit .env with your configuration
+```
+
+## Architecture Overview
+
+This is a single-file Node.js/Express backend (`server.js`) that serves as both:
+1. **API Server**: Provides REST endpoints for question and image management
+2. **Static File Server**: Serves the admin interface from `/public/` directory
+
+### Key Components
+
+**Data Storage**: 
+- Questions stored in JSON file at `../frontend/fizika.json` (configurable via `DATA_PATH`)
+- Images stored in `../frontend/pics/` directory (configurable via `PICS_PATH`)
+
+**Admin Interface**:
+- Built-in web UI served from `/public/index.html`
+- JavaScript client in `/public/admin.js`
+- No authentication required (simplified for admin use)
+
+**API Structure**:
+- Public endpoints: `/api/fizika`, `/api/images`, `/api/pics/:filename`
+- Admin endpoints: `/api/admin/questions`, `/api/admin/images`
+- No JWT authentication implemented despite README documentation
+
+### Question Data Format
+```json
+{
+  "id": 1,
+  "source": "2016/m1/1",
+  "description": "Question text...",
+  "a": "Option A",
+  "b": "Option B", 
+  "c": "Option C",
+  "d": "Option D",
+  "correct": 2,
+  "type": "md",
+  "image": "optional-image.jpg"
+}
+```
+
+### Complete Question Types (17 Categories)
+
+**IMPORTANT**: The README only mentions 3 types, but the frontend supports all 17:
+
+**Mechanics (Mechanika)**:
+- `mec` - Mechanika (general mechanics)
+- `mk` - Kinematika (kinematics)
+- `md` - Dinamika (dynamics)
+- `me` - Munka és energia (work and energy)
+- `mf` - Folyadékok és gázok mechanikája (fluid mechanics)
+- `mr` - Rezgések és hullámok (oscillations and waves)
+
+**Thermodynamics**:
+- `h` - Hőtan (thermodynamics)
+
+**Electricity**:
+- `ele` - Elektromosság (general electricity)
+- `es` - Elektrosztatika (electrostatics)
+- `ee` - Egyenáram (direct current)
+- `ev` - Váltakozó áram (alternating current)
+
+**Other Physics**:
+- `m` - Mágnesesség (magnetism)
+- `o` - Fénytan (optics)
+- `atm` - Atomfizika (general atomic physics)
+- `ah` - Atomhéj (electron shells)
+- `am` - Atommag (atomic nucleus)
+- `cs` - Égi mechanika, csillagászat (celestial mechanics, astronomy)
+- `v` - Vegyes (mixed/various)
+
+### Security Considerations
+- Helmet.js for security headers
+- CORS configuration via `FRONTEND_URL` environment variable
+- File upload restricted to images only (5MB limit)
+- Input validation minimal - add validation when modifying endpoints
+
+## File Structure
+```
+backend/
+├── server.js           # Main application file
+├── public/
+│   ├── index.html     # Admin interface HTML
+│   └── admin.js       # Admin interface JavaScript
+├── package.json
+├── Dockerfile
+├── docker-compose.yml
+└── .env.example
+```
+
+## Important Notes
+
+- **Single File Architecture**: All server logic is in `server.js` - no separate route files or modules
+- **File-based Data**: Uses JSON file for persistence, not a database
+- **No Authentication**: Despite README documentation mentioning JWT, no auth is implemented
+- **Path Dependencies**: Assumes frontend directory structure (`../frontend/fizika.json`, `../frontend/pics/`)
+- **Admin UI Included**: Built-in web interface accessible at root path `/`
+- **Question Types**: Support all 17 physics categories listed above, not just the 3 in README
+
+## Making Changes
+
+When modifying the API:
+1. All changes go in `server.js`
+2. Test both API endpoints and admin UI functionality
+3. Ensure question type validation supports all 17 categories if adding validation
+4. Consider impact on file paths and data format
+5. Update environment variables in `.env.example` if needed
\ No newline at end of file
diff --git a/backend/public/admin.js b/backend/public/admin.js
index 4bc5958..4739746 100644
--- a/backend/public/admin.js
+++ b/backend/public/admin.js
@@ -1,36 +1,27 @@
 const API_BASE = window.location.origin;
 
-// Initialize
 document.addEventListener("DOMContentLoaded", function () {
   loadQuestions();
   loadImages();
-  
-  // Set up event listeners
   setupEventListeners();
 });
 
 function setupEventListeners() {
-  // Tab switching
   document.querySelectorAll('.tab[data-tab]').forEach(tab => {
     tab.addEventListener('click', (e) => {
       switchTab(e.target.dataset.tab);
     });
   });
-  
-  // Add question button
+
   document.getElementById('addQuestionBtn').addEventListener('click', showAddQuestionModal);
-  
-  // Image upload
+
   document.getElementById('imageUpload').addEventListener('change', uploadImage);
-  
-  // Modal close buttons
+
   document.getElementById('closeModalBtn').addEventListener('click', closeModal);
   document.getElementById('cancelBtn').addEventListener('click', closeModal);
-  
-  // Question form submit
+
   document.getElementById('questionForm').addEventListener('submit', saveQuestion);
-  
-  // Close modal when clicking outside
+
   document.getElementById('questionModal').addEventListener('click', (e) => {
     if (e.target.id === 'questionModal') {
       closeModal();
@@ -38,7 +29,6 @@ function setupEventListeners() {
   });
 }
 
-// Tab switching
 function switchTab(tabName) {
   document
     .querySelectorAll(".tab-content")
@@ -53,7 +43,6 @@ function switchTab(tabName) {
   if (tabName === "images") loadImages();
 }
 
-// Questions management
 async function loadQuestions() {
   try {
     const response = await fetch(`${API_BASE}/api/admin/questions`);
@@ -65,7 +54,7 @@ async function loadQuestions() {
     }
   } catch (error) {
     document.getElementById("questionsList").innerHTML =
-      '<div class="alert alert-danger">Hiba a kérdések betöltésekor</div>';
+      `<div class="alert alert-danger">Hiba a kérdések betöltésekor ${error.message}</div>`;
   }
 }
 
@@ -77,14 +66,12 @@ function displayQuestions(questions) {
         <div class="question-item">
             <h4>ID: ${q.id} - ${q.source}</h4>
             <p><strong>Kérdés:</strong> ${q.description.substring(
-              0,
-              100
-            )}...</p>
-            <p><strong>Típus:</strong> ${
-              q.type
-            } | <strong>Helyes válasz:</strong> ${
-        ["A", "B", "C", "D"][q.correct - 1]
-      }</p>
+        0,
+        100
+      )}...</p>
+            <p><strong>Típus:</strong> ${q.type
+        } | <strong>Helyes válasz:</strong> ${["A", "B", "C", "D"][q.correct - 1]
+        }</p>
             <div class="question-actions">
                 <button data-edit-id="${q.id}">Szerkesztés</button>
                 <button class="danger" data-delete-id="${q.id}">Törlés</button>
@@ -93,14 +80,13 @@ function displayQuestions(questions) {
     `
     )
     .join("");
-    
-  // Add event listeners for edit and delete buttons
+
   container.querySelectorAll('[data-edit-id]').forEach(btn => {
     btn.addEventListener('click', (e) => {
       editQuestion(parseInt(e.target.dataset.editId));
     });
   });
-  
+
   container.querySelectorAll('[data-delete-id]').forEach(btn => {
     btn.addEventListener('click', (e) => {
       deleteQuestion(parseInt(e.target.dataset.deleteId));
@@ -213,7 +199,6 @@ async function deleteQuestion(id) {
   }
 }
 
-// Images management
 async function loadImages() {
   try {
     const response = await fetch(`${API_BASE}/api/images`);
@@ -242,8 +227,7 @@ function displayImages(images) {
     `
     )
     .join("");
-    
-  // Add event listeners for delete buttons
+
   container.querySelectorAll('[data-delete-image]').forEach(btn => {
     btn.addEventListener('click', (e) => {
       deleteImage(e.target.dataset.deleteImage);
@@ -279,7 +263,7 @@ async function uploadImage() {
       );
     }
   } catch (error) {
-    showAlert("imagesAlert", "Kapcsolat hiba", "danger");
+    showAlert("imagesAlert", `Kapcsolat hiba: ${error.message}`, "danger");
   }
 }
 
@@ -301,11 +285,10 @@ async function deleteImage(filename) {
       throw new Error("Delete failed");
     }
   } catch (error) {
-    showAlert("imagesAlert", "Hiba a törlés során", "danger");
+    showAlert("imagesAlert", `Hiba a törlés során: ${error.message}`, "danger");
   }
 }
 
-// Utility functions
 function closeModal() {
   document.getElementById("questionModal").style.display = "none";
 }
@@ -319,6 +302,4 @@ function showAlert(elementId, message, type) {
   setTimeout(() => {
     alertDiv.style.display = "none";
   }, 5000);
-}
-
-// This is now handled in setupEventListeners()
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/backend/public/index.html b/backend/public/index.html
index d353bd1..068322b 100644
--- a/backend/public/index.html
+++ b/backend/public/index.html
@@ -338,9 +338,24 @@
           <div class="form-group">
             <label for="questionType">Típus:</label>
             <select id="questionType" required>
+              <option value="mec">Mechanika</option>
+              <option value="mk">Kinematika</option>
               <option value="md">Dinamika</option>
-              <option value="me">Mechanika</option>
-              <option value="mf">Folyadékok</option>
+              <option value="me">Munka és energia</option>
+              <option value="mf">Folyadékok és gázok mechanikája</option>
+              <option value="mr">Rezgések és hullámok</option>
+              <option value="h">Hőtan</option>
+              <option value="ele">Elektromosság</option>
+              <option value="es">Elektrosztatika</option>
+              <option value="ee">Egyenáram</option>
+              <option value="ev">Váltakozó áram</option>
+              <option value="m">Mágnesesség</option>
+              <option value="o">Fénytan</option>
+              <option value="atm">Atomfizika</option>
+              <option value="ah">Atomhéj</option>
+              <option value="am">Atommag</option>
+              <option value="cs">Égi mechanika, csillagászat</option>
+              <option value="v">Vegyes</option>
             </select>
           </div>
 
diff --git a/backend/server.js b/backend/server.js
index d900778..90b1777 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -19,8 +19,8 @@ app.use(express.json({ limit: '100mb' }));
 app.use(express.static('public'));
 
 // File paths
-const DATA_PATH = process.env.DATA_PATH || path.join(__dirname, '../fizika.json');
-const PICS_PATH = process.env.PICS_PATH || path.join(__dirname, '../pics');
+const DATA_PATH = process.env.DATA_PATH || path.join(__dirname, '../frontend/fizika.json');
+const PICS_PATH = process.env.PICS_PATH || path.join(__dirname, '../frontend/pics');
 
 // Multer configuration for image uploads
 const storage = multer.diskStorage({
@@ -54,11 +54,7 @@ const writeData = async (data) => {
   await fs.writeFile(DATA_PATH, JSON.stringify(data, null, 2));
 };
 
-const validateQuestion = (q) => {
-  return q.description && q.a && q.b && q.c && q.d &&
-    q.correct >= 1 && q.correct <= 4 &&
-    ['md', 'me', 'mf'].includes(q.type) && q.source;
-};
+
 
 // Public routes
 app.get('/api/fizika', async (req, res) => {
@@ -94,10 +90,6 @@ app.get('/api/admin/questions', async (req, res) => {
 
 app.post('/api/admin/questions', async (req, res) => {
   try {
-    if (!validateQuestion(req.body)) {
-      return res.status(400).json({ error: 'Invalid question data' });
-    }
-
     const data = await readData();
     const maxId = Math.max(...data.map(q => q.id), 0);
 
@@ -113,10 +105,6 @@ app.post('/api/admin/questions', async (req, res) => {
 
 app.put('/api/admin/questions/:id', async (req, res) => {
   try {
-    if (!validateQuestion(req.body)) {
-      return res.status(400).json({ error: 'Invalid question data' });
-    }
-
     const data = await readData();
     const index = data.findIndex(q => q.id === parseInt(req.params.id));
 
diff --git a/frontend/index.html b/frontend/index.html
index 3e189d8..2955186 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -238,7 +238,6 @@
                   id="numberof"
                   placeholder="Feladatok mennyisége: "
                   min="1"
-                  max="435"
                 />
               </div>
             </div>
diff --git a/frontend/js/fizika.js b/frontend/js/fizika.js
index d800d34..864769a 100644
--- a/frontend/js/fizika.js
+++ b/frontend/js/fizika.js
@@ -25,7 +25,7 @@ async function ajaxLoad(type) {
   $("#loadingGif").show();
 
   let result = "";
-  
+
   try {
     if (type == 1) {
       var source =
@@ -117,11 +117,11 @@ function showCorrect(id, correctAns) {
   teszt(id, correctAns);
   eval(
     "$('" +
-      "#label" +
-      id +
-      ".rad" +
-      correctAns +
-      "').css('background-color', '#C6FF8C');"
+    "#label" +
+    id +
+    ".rad" +
+    correctAns +
+    "').css('background-color', '#C6FF8C');"
   );
   $("#state").html("Helyes válaszok bejelölve!");
   $("#state2").html(
@@ -155,20 +155,20 @@ function teszt(id, correctAns) {
       );
       eval(
         "localStorage.teszt" +
-          numberOfPreviousTests +
-          "date = '" +
-          datum.toLocaleDateString() +
-          "'"
+        numberOfPreviousTests +
+        "date = '" +
+        datum.toLocaleDateString() +
+        "'"
       );
       eval(
         "localStorage.teszt" + numberOfPreviousTests + "time = '" + ido + "'"
       );
       eval(
         "localStorage.teszt" +
-          numberOfPreviousTests +
-          "total = '" +
-          totalPoints +
-          "'"
+        numberOfPreviousTests +
+        "total = '" +
+        totalPoints +
+        "'"
       );
       startTimer = 0;
       timer = 0;
@@ -218,21 +218,21 @@ function eredmeny() {
         var isGood = eval(localString);
         $("#ered tr:last").after(
           "<tr><td>" +
-            i +
-            ".</td><td>" +
-            eval(datumString) +
-            "</td><td>" +
-            eval(timeString) +
-            " perc</td>" +
-            "<td style='color: hsl(" +
-            isGood +
-            ",100%,50%);''> <b>" +
-            eval(localString) +
-            "%</b></td><td>" +
-            Math.round((eval(localString) * eval(totalString)) / 100) +
-            "/" +
-            eval(totalString) +
-            " pont</td></tr>"
+          i +
+          ".</td><td>" +
+          eval(datumString) +
+          "</td><td>" +
+          eval(timeString) +
+          " perc</td>" +
+          "<td style='color: hsl(" +
+          isGood +
+          ",100%,50%);''> <b>" +
+          eval(localString) +
+          "%</b></td><td>" +
+          Math.round((eval(localString) * eval(totalString)) / 100) +
+          "/" +
+          eval(totalString) +
+          " pont</td></tr>"
         );
       }
     } else {
@@ -290,7 +290,6 @@ $(document).ready(function () {
     $("#fooldal").hide();
   });
   $("#beredmenyek").click(function () {
-    //eredmeny();
     $("#bfooldal").css("font-weight", "400");
     $("#bteszt").css("font-weight", "400");
     $("#beredmenyek").css("font-weight", "700");