feat(ui): Slider mit Vor-/Zurück-Buttons und Touch/Mouse-Drag für Warengruppen

public/index.html

@@ -154,20 +154,54 @@
       display: none;
     }
 
-    /* Swipebar Kategorien */
-    .category-swipe-wrapper {
+    /* Interaktiver Slider / Swipe Container */
+    .slider-nav-container {
       position: relative;
+      display: flex;
+      align-items: center;
       margin: 0 -16px;
-      padding: 0 16px;
+      padding: 0 8px;
+    }
+
+    .slider-arrow {
+      background: var(--card-bg);
+      border: 1px solid var(--card-border);
+      color: var(--text);
+      width: 32px;
+      height: 32px;
+      border-radius: 50%;
+      display: flex;
+      align-items: center;
+      justify-content: center;
+      cursor: pointer;
+      font-size: 14px;
+      z-index: 2;
+      flex-shrink: 0;
+      backdrop-filter: blur(10px);
+      transition: all 0.2s;
+    }
+
+    .slider-arrow:hover {
+      background: var(--primary);
+      color: var(--bg);
+      border-color: var(--primary);
     }
 
     .category-swipe {
       display: flex;
       gap: 8px;
       overflow-x: auto;
-      padding-bottom: 4px;
+      scroll-behavior: smooth;
+      padding: 6px 8px;
       scrollbar-width: none;
       -webkit-overflow-scrolling: touch;
+      flex: 1;
+      cursor: grab;
+      user-select: none;
+    }
+
+    .category-swipe:active {
+      cursor: grabbing;
     }
 
     .category-swipe::-webkit-scrollbar {
@@ -176,7 +210,7 @@
 
     .category-pill {
       flex: 0 0 auto;
-      padding: 8px 16px;
+      padding: 8px 18px;
       border-radius: 999px;
       font-size: 13px;
       font-weight: 600;
@@ -185,20 +219,24 @@
       border: 1px solid var(--card-border);
       cursor: pointer;
       white-space: nowrap;
-      transition: all 0.2s ease;
-      user-select: none;
+      transition: all 0.25s ease;
+      display: inline-flex;
+      align-items: center;
+      gap: 6px;
     }
 
     .category-pill:hover {
       color: var(--text);
       border-color: rgba(255, 255, 255, 0.2);
+      transform: translateY(-1px);
     }
 
     .category-pill.active {
       background: var(--primary);
       color: var(--bg);
       border-color: var(--primary);
-      box-shadow: 0 0 12px var(--primary-glow);
+      box-shadow: 0 0 14px var(--primary-glow);
+      transform: scale(1.03);
     }
 
     .section-title {
@@ -320,11 +358,13 @@
       <button id="clear-search" class="clear-search">✕</button>
     </div>
 
-    <!-- Swipebar Warengruppen -->
-    <div class="category-swipe-wrapper">
+    <!-- Warengruppen Slider mit Pfeilen & Touch Drag -->
+    <div class="slider-nav-container">
+      <button id="slide-left" class="slider-arrow" aria-label="Zurück">‹</button>
       <div id="category-swipe" class="category-swipe">
         <button class="category-pill active" data-id="all">Alle Artikel</button>
       </div>
+      <button id="slide-right" class="slider-arrow" aria-label="Weiter">›</button>
     </div>
 
     <!-- Getränkeliste -->
@@ -351,12 +391,12 @@
         const data = await res.json();
         allCategories = data.categories || [];
 
-        // Globale Texte & Theme anwenden
         if (data.settings) {
           applySettings(data.settings);
         }
 
         renderCategoryPills();
+        initSliderControls();
         renderMenu();
       } catch (err) {
         container.innerHTML = '<div class="card" style="color:#ef4444; text-align:center;">Fehler beim Laden der Speisekarte.</div>';
@@ -372,7 +412,6 @@
       if (s.site_badge) document.getElementById('site-badge').textContent = s.site_badge;
       if (s.site_footer) document.getElementById('site-footer').textContent = s.site_footer;
 
-      // Theme CSS Variablen dynamisch setzen
       const root = document.documentElement;
       if (s.theme_bg) root.style.setProperty('--bg', s.theme_bg);
       if (s.theme_card_bg) root.style.setProperty('--card-bg', s.theme_card_bg);
@@ -399,7 +438,7 @@
       swipeEl.innerHTML = pillsHtml;
 
       swipeEl.querySelectorAll('.category-pill').forEach(btn => {
-        btn.addEventListener('click', (e) => {
+        btn.addEventListener('click', () => {
           swipeEl.querySelectorAll('.category-pill').forEach(b => b.classList.remove('active'));
           btn.classList.add('active');
           activeCategoryId = btn.dataset.id;
@@ -409,6 +448,43 @@
       });
     }
 
+    // Slider Controls (Pfeile + Mouse Drag)
+    function initSliderControls() {
+      const slider = document.getElementById('category-swipe');
+      const btnLeft = document.getElementById('slide-left');
+      const btnRight = document.getElementById('slide-right');
+
+      btnLeft.addEventListener('click', () => {
+        slider.scrollBy({ left: -160, behavior: 'smooth' });
+      });
+
+      btnRight.addEventListener('click', () => {
+        slider.scrollBy({ left: 160, behavior: 'smooth' });
+      });
+
+      // Mouse Drag Unterstützung am Desktop
+      let isDown = false;
+      let startX;
+      let scrollLeft;
+
+      slider.addEventListener('mousedown', (e) => {
+        isDown = true;
+        startX = e.pageX - slider.offsetLeft;
+        scrollLeft = slider.scrollLeft;
+      });
+
+      slider.addEventListener('mouseleave', () => { isDown = false; });
+      slider.addEventListener('mouseup', () => { isDown = false; });
+
+      slider.addEventListener('mousemove', (e) => {
+        if (!isDown) return;
+        e.preventDefault();
+        const x = e.pageX - slider.offsetLeft;
+        const walk = (x - startX) * 1.5;
+        slider.scrollLeft = scrollLeft - walk;
+      });
+    }
+
     function renderMenu() {
       const container = document.getElementById('menu-container');
       const query = searchQuery.trim().toLowerCase();