diff --git a/app.py b/app.py
index 7d8498b..e036b27 100644
--- a/app.py
+++ b/app.py
@@ -1543,7 +1543,7 @@ def handle_disconnect(sid):
 @socketio.on("add_item")
 def handle_add_item(data):
     list_id = data["list_id"]
-    name = data["name"]
+    name = data["name"].strip()
     quantity = data.get("quantity", 1)
 
     try:
@@ -1553,34 +1553,56 @@ def handle_add_item(data):
     except:
         quantity = 1
 
-    new_item = Item(
-        list_id=list_id,
-        name=name,
-        quantity=quantity,
-        added_by=current_user.id if current_user.is_authenticated else None,
-    )
-    db.session.add(new_item)
+    # Szukamy istniejącego itemu w tej liście (ignorując wielkość liter)
+    existing_item = Item.query.filter(
+        Item.list_id == list_id,
+        func.lower(Item.name) == name.lower(),
+        Item.not_purchased == False
+    ).first()
 
-    if not SuggestedProduct.query.filter_by(name=name).first():
-        new_suggestion = SuggestedProduct(name=name)
-        db.session.add(new_suggestion)
+    if existing_item:
+        existing_item.quantity += quantity
+        db.session.commit()
 
-    db.session.commit()
+        emit(
+            "item_edited",
+            {
+                "item_id": existing_item.id,
+                "new_name": existing_item.name,
+                "new_quantity": existing_item.quantity
+            },
+            to=str(list_id),
+        )
+    else:
+        new_item = Item(
+            list_id=list_id,
+            name=name,
+            quantity=quantity,
+            added_by=current_user.id if current_user.is_authenticated else None,
+        )
+        db.session.add(new_item)
 
-    emit(
-        "item_added",
-        {
-            "id": new_item.id,
-            "name": new_item.name,
-            "quantity": new_item.quantity,
-            "added_by": (
-                current_user.username if current_user.is_authenticated else "Gość"
-            ),
-        },
-        to=str(list_id),
-        include_self=True,
-    )
+        if not SuggestedProduct.query.filter(func.lower(SuggestedProduct.name) == name.lower()).first():
+            new_suggestion = SuggestedProduct(name=name)
+            db.session.add(new_suggestion)
 
+        db.session.commit()
+
+        emit(
+            "item_added",
+            {
+                "id": new_item.id,
+                "name": new_item.name,
+                "quantity": new_item.quantity,
+                "added_by": (
+                    current_user.username if current_user.is_authenticated else "Gość"
+                ),
+            },
+            to=str(list_id),
+            include_self=True,
+        )
+
+    # Aktualizacja postępu
     purchased_count, total_count, percent = get_progress(list_id)
 
     emit(
diff --git a/static/js/functions.js b/static/js/functions.js
index 533a179..ac36d16 100644
--- a/static/js/functions.js
+++ b/static/js/functions.js
@@ -217,7 +217,7 @@ function applyHidePurchased(isInit = false) {
 }
 
 function toggleVisibility(listId) {
-  fetch('/toggle_visibility/' + listId, {method: 'POST'})
+  fetch('/toggle_visibility/' + listId, { method: 'POST' })
     .then(response => response.json())
     .then(data => {
       const shareHeader = document.getElementById('share-header');
@@ -297,10 +297,9 @@ function updateListSmoothly(newItems) {
     }
 
     // Klasy tła
-    li.className = `list-group-item d-flex justify-content-between align-items-center flex-wrap clickable-item ${
-      item.purchased ? 'bg-success text-white' :
+    li.className = `list-group-item d-flex justify-content-between align-items-center flex-wrap clickable-item ${item.purchased ? 'bg-success text-white' :
       item.not_purchased ? 'bg-warning text-dark' : 'item-not-checked'
-    }`;
+      }`;
 
     // HTML wewnętrzny
     li.innerHTML = `
@@ -317,7 +316,7 @@ function updateListSmoothly(newItems) {
       </div>
       <div class="btn-group btn-group-sm" role="group">
         ${item.not_purchased ? `
-          <button type="button" class="btn btn-outline-success"
+          <button type="button" class="btn btn-outline-light me-auto"
             onclick="unmarkNotPurchased(${item.id})">
             ✅ Przywróć
           </button>
@@ -334,11 +333,11 @@ function updateListSmoothly(newItems) {
           ` : ''}
         `}
         ${!window.IS_SHARE ? `
-          <button type="button" class="btn btn-outline-warning"
+          <button type="button" class="btn btn-outline-light"
             onclick="editItem(${item.id}, '${item.name.replace(/'/g, "\\'")}', ${item.quantity || 1})">
             ✏️
           </button>
-          <button type="button" class="btn btn-outline-danger"
+          <button type="button" class="btn btn-outline-light"
             onclick="deleteItem(${item.id})">
             🗑️
           </button>
@@ -358,7 +357,7 @@ function updateListSmoothly(newItems) {
 }
 
 
-document.addEventListener("DOMContentLoaded", function() {
+document.addEventListener("DOMContentLoaded", function () {
   const receiptSection = document.getElementById("receiptSection");
   const toggleBtn = document.querySelector('[data-bs-target="#receiptSection"]');
 
@@ -377,14 +376,14 @@ document.addEventListener("DOMContentLoaded", function() {
   });
 });
 
-document.addEventListener("DOMContentLoaded", function() {
+document.addEventListener("DOMContentLoaded", function () {
   const toggle = document.getElementById('hidePurchasedToggle');
   if (!toggle) return;
 
   const savedState = localStorage.getItem('hidePurchasedToggle');
   toggle.checked = savedState === 'true';
   applyHidePurchased(true);
-  toggle.addEventListener('change', function() {
+  toggle.addEventListener('change', function () {
     localStorage.setItem('hidePurchasedToggle', toggle.checked ? 'true' : 'false');
     applyHidePurchased();
   });
diff --git a/static/js/live.js b/static/js/live.js
index d48ae68..9cc05c3 100644
--- a/static/js/live.js
+++ b/static/js/live.js
@@ -144,11 +144,11 @@ function setupList(listId, username) {
       <span id="name-${data.id}" class="text-white">${data.name} ${quantityBadge}</span>
     </div>
     <div class="btn-group btn-group-sm" role="group">
-      <button type="button" class="btn btn-outline-warning"
+      <button type="button" class="btn btn-outline-light"
         onclick="editItem(${data.id}, '${data.name.replace(/'/g, "\\'")}', ${data.quantity || 1})">
         ✏️
       </button>
-      <button type="button" class="btn btn-outline-danger"
+      <button type="button" class="btn btn-outline-light"
         onclick="deleteItem(${data.id})">
         🗑️
       </button>
@@ -156,6 +156,7 @@ function setupList(listId, username) {
   `;
 
     document.getElementById('items').prepend(li);
+    toggleEmptyPlaceholder();
   });
 
   socket.on('item_deleted', data => {
diff --git a/static/js/mass_add.js b/static/js/mass_add.js
index 0265f35..495517e 100644
--- a/static/js/mass_add.js
+++ b/static/js/mass_add.js
@@ -2,11 +2,16 @@ document.addEventListener('DOMContentLoaded', function () {
   const modal = document.getElementById('massAddModal');
   const productList = document.getElementById('mass-add-list');
 
+  // Funkcja normalizacji (usuwa diakrytyki i zamienia na lowercase)
+  function normalize(str) {
+    return str.normalize("NFD").replace(/[\u0300-\u036f]/g, "").toLowerCase();
+  }
+
   modal.addEventListener('show.bs.modal', async function () {
     let addedProducts = new Set();
     document.querySelectorAll('#items li').forEach(li => {
       if (li.dataset.name) {
-        addedProducts.add(li.dataset.name.toLowerCase());
+        addedProducts.add(normalize(li.dataset.name));
       }
     });
 
@@ -20,8 +25,7 @@ document.addEventListener('DOMContentLoaded', function () {
         const li = document.createElement('li');
         li.className = 'list-group-item d-flex justify-content-between align-items-center bg-dark text-light';
 
-        if (addedProducts.has(name.toLowerCase())) {
-          // Produkt już dodany — oznacz jako nieaktywny
+        if (addedProducts.has(normalize(name))) {
           const nameSpan = document.createElement('span');
           nameSpan.textContent = name;
           li.appendChild(nameSpan);
@@ -32,17 +36,14 @@ document.addEventListener('DOMContentLoaded', function () {
           badge.textContent = 'Dodano';
           li.appendChild(badge);
         } else {
-          // Nazwa produktu
           const nameSpan = document.createElement('span');
           nameSpan.textContent = name;
           nameSpan.style.flex = '1 1 auto';
           li.appendChild(nameSpan);
 
-          // Kontener na minus, pole i plus
           const qtyWrapper = document.createElement('div');
           qtyWrapper.className = 'd-flex align-items-center ms-2 quantity-controls';
 
-          // Minus
           const minusBtn = document.createElement('button');
           minusBtn.type = 'button';
           minusBtn.className = 'btn btn-outline-light btn-sm px-2';
@@ -51,18 +52,15 @@ document.addEventListener('DOMContentLoaded', function () {
             qty.value = Math.max(1, parseInt(qty.value) - 1);
           };
 
-          // Pole ilości
           const qty = document.createElement('input');
           qty.type = 'number';
           qty.min = 1;
           qty.value = 1;
-          qty.className = 'form-control text-center p-1';
-          qty.classList.add('rounded');
+          qty.className = 'form-control text-center p-1 rounded';
           qty.style.width = '50px';
           qty.style.margin = '0 2px';
           qty.title = 'Ilość';
 
-          // Plus
           const plusBtn = document.createElement('button');
           plusBtn.type = 'button';
           plusBtn.className = 'btn btn-outline-light btn-sm px-2';
@@ -75,7 +73,6 @@ document.addEventListener('DOMContentLoaded', function () {
           qtyWrapper.appendChild(qty);
           qtyWrapper.appendChild(plusBtn);
 
-          // Przycisk dodania
           const btn = document.createElement('button');
           btn.className = 'btn btn-sm btn-primary ms-4';
           btn.textContent = '+';
@@ -99,25 +96,19 @@ document.addEventListener('DOMContentLoaded', function () {
     document.querySelectorAll('#mass-add-list li').forEach(li => {
       const itemName = li.firstChild.textContent.trim();
 
-      if (itemName === data.name && !li.classList.contains('opacity-50')) {
-        // Usuń wszystkie dzieci
+      if (normalize(itemName) === normalize(data.name) && !li.classList.contains('opacity-50')) {
         while (li.firstChild) {
           li.removeChild(li.firstChild);
         }
 
-        // Ustaw nazwę
         li.textContent = data.name;
-
-        // Dodaj klasę wyszarzenia
         li.classList.add('opacity-50');
 
-        // Dodaj badge
         const badge = document.createElement('span');
         badge.className = 'badge bg-success ms-auto';
         badge.textContent = 'Dodano';
         li.appendChild(badge);
 
-        // Zablokuj kliknięcia
         li.onclick = null;
       }
     });
diff --git a/templates/list.html b/templates/list.html
index 9f3c548..6c76190 100644
--- a/templates/list.html
+++ b/templates/list.html
@@ -84,7 +84,7 @@
   <label class="form-check-label ms-2" for="hidePurchasedToggle">Ukryj zaznaczone</label>
 </div>
 
-<ul id="items" class="list-group mb-3">
+<ul id="items" class="list-group mb-3" data-is-share="{{ 'true' if is_share else 'false' }}">
   {% for item in items %}
   <li data-name="{{ item.name|lower }}" id="item-{{ item.id }}"
     class="list-group-item d-flex justify-content-between align-items-center flex-wrap clickable-item 
diff --git a/templates/list_share.html b/templates/list_share.html
index cb0dec7..f20b0e0 100644
--- a/templates/list_share.html
+++ b/templates/list_share.html
@@ -25,13 +25,12 @@
   <label class="form-check-label ms-2" for="hidePurchasedToggle">Ukryj zaznaczone</label>
 </div>
 
-<ul id="items" class="list-group mb-3">
+<ul id="items" class="list-group mb-3" data-is-share="{{ 'true' if is_share else 'false' }}">
   {% for item in items %}
 
   <li data-name="{{ item.name|lower }}" id="item-{{ item.id }}"
     class="list-group-item d-flex justify-content-between align-items-center flex-wrap clickable-item 
-            {% if item.purchased %}bg-success text-white{% elif item.not_purchased %}bg-warning text-dark{% else %}item-not-checked{% endif %}"
-    data-is-share="{{ 'true' if is_share else 'false' }}">
+            {% if item.purchased %}bg-success text-white{% elif item.not_purchased %}bg-warning text-dark{% else %}item-not-checked{% endif %}">
 
     <div class="d-flex align-items-center gap-3 flex-grow-1">