Add custom product with full nutrients, bigger + buttons with border

Custom product:
- "+" button next to search on Products tab
- showAddProductModal: name, KBJU, + all MICRO_FIELDS (34 nutrient fields)
- All optional except name
- Creates product with source="manual"
- Refreshes search after save

Button style:
- .add-btn: 0.5px border with primary color, rounded corners (6px)
- Min 40x36px for finger-friendly tapping on retina
- Flexbox centered content

frontend/css/styles.css

@@ -478,12 +478,18 @@ select {
 
 .add-btn {
   background: none;
-  border: none;
+  border: 0.5px solid var(--primary);
+  border-radius: 6px;
   color: var(--primary);
   font-size: 22px;
   line-height: 1;
   cursor: pointer;
-  padding: 0 4px;
+  padding: 4px 10px;
+  min-width: 40px;
+  min-height: 36px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 .log-list {

frontend/js/main.js

@@ -1197,8 +1197,11 @@ async function renderProducts(container) {
         <button class="sub-tab" data-tab="recipes">Рецепты</button>
       </div>
       <div id="products-tab">
-        <input id="prod-search" class="search-input" type="search"
-               placeholder="Название, бренд или ингредиент..." />
+        <div style="display:flex;gap:8px;align-items:center">
+          <input id="prod-search" class="search-input" type="search" style="flex:1"
+                 placeholder="Название, бренд или ингредиент..." />
+          <button class="add-btn" id="add-custom-product" title="Свой продукт">+</button>
+        </div>
         <div id="prod-count" class="prod-count"></div>
         <div id="prod-results" class="prod-list"></div>
       </div>
@@ -1339,6 +1342,65 @@ async function renderProducts(container) {
 
   listEl.innerHTML = `<div class="prod-hint">Введите название продукта</div>`;
   input.focus();
+
+  // Add custom product button
+  const addCustomBtn = container.querySelector("#add-custom-product");
+  if (addCustomBtn) addCustomBtn.onclick = () => showAddProductModal(() => doSearch(true));
+}
+
+function showAddProductModal(onSaved) {
+  const microHtml = MICRO_FIELDS.map(f => {
+    return `<div class="form-group micro-field">
+      <label>${f.label}</label>
+      <input id="np-${f.key}" type="number" inputmode="decimal" step="any" placeholder="—" />
+    </div>`;
+  }).join("");
+
+  showModal(`
+    <h3>Новый продукт</h3>
+    <div class="form-group">
+      <label>Название</label>
+      <input id="np-name" type="text" placeholder="Тесто для чебуреков" />
+    </div>
+    <div style="display:flex;gap:8px">
+      <div class="form-group" style="flex:1">
+        <label>ккал/100г</label>
+        <input id="np-kcal" type="number" inputmode="decimal" placeholder="260" />
+      </div>
+      <div class="form-group" style="flex:1">
+        <label>Б</label>
+        <input id="np-protein" type="number" inputmode="decimal" step="0.1" placeholder="7" />
+      </div>
+      <div class="form-group" style="flex:1">
+        <label>Ж</label>
+        <input id="np-fat" type="number" inputmode="decimal" step="0.1" placeholder="4" />
+      </div>
+      <div class="form-group" style="flex:1">
+        <label>У</label>
+        <input id="np-carbs" type="number" inputmode="decimal" step="0.1" placeholder="48" />
+      </div>
+    </div>
+    <p style="color:var(--muted);font-size:12px;margin:8px 0 4px">Нутриенты на 100г (опционально):</p>
+    <div class="micro-grid">${microHtml}</div>`,
+  async overlay => {
+    const name = overlay.querySelector("#np-name").value.trim();
+    if (!name) return false;
+    const data = {
+      name,
+      kcal_per_100g: parseFloat(overlay.querySelector("#np-kcal").value) || null,
+      protein_per_100g: parseFloat(overlay.querySelector("#np-protein").value) || null,
+      fat_per_100g: parseFloat(overlay.querySelector("#np-fat").value) || null,
+      carbs_per_100g: parseFloat(overlay.querySelector("#np-carbs").value) || null,
+      source: "manual",
+    };
+    for (const f of MICRO_FIELDS) {
+      let val = parseFloat(overlay.querySelector(`#np-${f.key}`).value) || null;
+      if (val && f.mult) val *= f.mult;
+      data[f.key] = val;
+    }
+    await DB.addProduct(data);
+    if (onSaved) onSaved();
+  });
 }
 
 // ---------------------------------------------------------------------------