📱 Implement Mobile-First Responsive Design

🎯 Mobile Slide-In Navigation:
- Added mobile menu button with hamburger icon
- Implemented slide-in sidebar with smooth transitions
- Added mobile overlay with click-to-close functionality
- Mobile menu auto-closes when navigating to new pages
- Proper z-index layering for mobile interactions

🃏 Smart Card Panel Positioning:
- Panels now open on opposite side for right-edge cards
- Added cardIndex and cardsPerRow props to CardItem
- Dynamic positioning based on card's position in grid
- Prevents panels from extending off-screen edges
- Maintains hover functionality on desktop

📱 Mobile-Optimized Bulk Actions:
- Toolbar now spans full width on mobile devices
- Icon-only buttons on mobile, full labels on desktop
- Responsive spacing and padding adjustments
- Improved touch targets for mobile interaction
- Maintains functionality across all screen sizes

🎨 Enhanced Grid Layout:
- Improved mobile grid: 2 columns with tighter spacing
- Better space utilization on all device sizes
- Responsive gap spacing that adapts to screen size
- Optimized padding for mobile vs desktop
- Cards now fill available space properly

✅ Cross-Device Experience:
- Mobile: Slide-in nav, icon-only actions, 2-column grid
- Tablet: Responsive layout with appropriate spacing
- Desktop: Full sidebar, labeled actions, hover panels
- Large screens: Maximum columns with side panel space

The app now provides an optimal mobile experience while maintaining desktop functionality! ��💻🖥️

components/BulkSelectionToolbar.js

@@ -42,51 +42,52 @@ export default function BulkSelectionToolbar({
   };
 
   return (
-    <div className="fixed bottom-6 left-1/2 transform -translate-x-1/2 z-50">
+    <div className="fixed bottom-4 left-4 right-4 sm:bottom-6 sm:left-1/2 sm:right-auto sm:transform sm:-translate-x-1/2 z-50">
-      <div className="bg-white rounded-xl shadow-2xl border border-gray-200 px-6 py-4 flex items-center space-x-4 min-w-96">
+      <div className="bg-white rounded-xl shadow-2xl border border-gray-200 px-3 sm:px-6 py-3 sm:py-4 flex items-center justify-between sm:justify-start sm:space-x-4 sm:min-w-96">
         {/* Selection Count */}
         <div className="flex items-center space-x-2">
           <div className="w-8 h-8 bg-purple-600 rounded-full flex items-center justify-center">
             <span className="text-white text-sm font-bold">{selectedCount}</span>
           </div>
-          <span className="text-gray-700 font-medium">
+          <span className="text-gray-700 font-medium text-sm sm:text-base">
-            {selectedCount} card{selectedCount !== 1 ? 's' : ''} selected
+            <span className="hidden sm:inline">{selectedCount} card{selectedCount !== 1 ? 's' : ''} selected</span>
+            <span className="sm:hidden">{selectedCount}</span>
           </span>
         </div>
 
-        {/* Divider */}
+        {/* Divider - Hidden on mobile */}
-        <div className="h-6 w-px bg-gray-300"></div>
+        <div className="hidden sm:block h-6 w-px bg-gray-300"></div>
 
         {/* Quick Actions */}
-        <div className="flex items-center space-x-2">
+        <div className="flex items-center space-x-1 sm:space-x-2">
           <button
             onClick={handleAddToCollection}
-            className="px-3 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 text-sm font-medium flex items-center space-x-1 transition-colors"
+            className="px-2 sm:px-3 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 text-sm font-medium flex items-center space-x-1 transition-colors"
           >
             <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10" />
             </svg>
-            <span>Collection</span>
+            <span className="hidden sm:inline">Collection</span>
           </button>
 
           <button
             onClick={handleAddToDeck}
-            className="px-3 py-2 bg-green-600 text-white rounded-lg hover:bg-green-700 text-sm font-medium flex items-center space-x-1 transition-colors"
+            className="px-2 sm:px-3 py-2 bg-green-600 text-white rounded-lg hover:bg-green-700 text-sm font-medium flex items-center space-x-1 transition-colors"
           >
             <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10" />
             </svg>
-            <span>Deck</span>
+            <span className="hidden sm:inline">Deck</span>
           </button>
 
           <button
             onClick={handleMarkAsOwned}
-            className="px-3 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 text-sm font-medium flex items-center space-x-1 transition-colors"
+            className="px-2 sm:px-3 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 text-sm font-medium flex items-center space-x-1 transition-colors"
           >
             <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
             </svg>
-            <span>Own</span>
+            <span className="hidden sm:inline">Own</span>
           </button>
         </div>
 

components/CardItem.js

@@ -9,7 +9,9 @@ export default function CardItem({
   onAddToCollection,
   onAddToDeck,
   onToggleFavorite,
-  isFavorited = false
+  isFavorited = false,
+  cardIndex = 0,
+  cardsPerRow = 4
 }) {
   const [imageError, setImageError] = useState(false);
   const router = useRouter();
@@ -75,6 +77,10 @@ export default function CardItem({
 
   const rarityEffects = getRarityEffects(card.rarity);
 
+  // Determine panel position based on card position in row
+  const isRightSide = (cardIndex % cardsPerRow) >= Math.floor(cardsPerRow / 2);
+  const panelPosition = isRightSide ? 'right' : 'left';
+
   if (viewMode === 'list') {
     return (
       <div 
@@ -253,8 +259,14 @@ export default function CardItem({
       </div>
 
       {/* Side Hover Panel */}
-      <div className={`card-side-panel absolute left-full top-0 ml-2 w-80 h-full transition-all duration-300 ease-out z-30 ${
+      <div className={`card-side-panel absolute ${
-        'opacity-0 translate-x-2 pointer-events-none group-hover:opacity-100 group-hover:translate-x-0 group-hover:pointer-events-auto delay-300 group-hover:delay-500'
+        panelPosition === 'right' 
+          ? 'right-full top-0 mr-2' 
+          : 'left-full top-0 ml-2'
+      } w-80 h-full transition-all duration-300 ease-out z-30 ${
+        panelPosition === 'right'
+          ? 'opacity-0 -translate-x-2 pointer-events-none group-hover:opacity-100 group-hover:translate-x-0 group-hover:pointer-events-auto delay-300 group-hover:delay-500'
+          : 'opacity-0 translate-x-2 pointer-events-none group-hover:opacity-100 group-hover:translate-x-0 group-hover:pointer-events-auto delay-300 group-hover:delay-500'
       }`}>
         <div className={`bg-white dark:bg-gray-800 rounded-xl border shadow-2xl h-full overflow-hidden ${
           rarityEffects.border !== 'border-gray-200' 

components/Layout.js

@@ -7,6 +7,7 @@ export default function Layout({ children, user = { email: 'me@randallstillwell.
   const router = useRouter();
   const { theme, toggleTheme } = useTheme();
   const [searchQuery, setSearchQuery] = useState('');
+  const [isMobileMenuOpen, setIsMobileMenuOpen] = useState(false);
 
   const navigation = [
     { name: 'Dashboard', href: '/dashboard', icon: 'grid', active: router.pathname === '/dashboard' },
@@ -87,10 +88,52 @@ export default function Layout({ children, user = { email: 'me@randallstillwell.
 
   return (
     <div className="flex h-screen" style={{ backgroundColor: 'var(--bg-primary)' }}>
+      {/* Mobile Menu Button */}
+      <button
+        onClick={() => setIsMobileMenuOpen(true)}
+        className="lg:hidden fixed top-4 left-4 z-50 p-2 rounded-lg shadow-lg"
+        style={{ backgroundColor: 'var(--bg-secondary)', color: 'var(--text-primary)' }}
+      >
+        <svg className="h-6 w-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 6h16M4 12h16M4 18h16" />
+        </svg>
+      </button>
+
+      {/* Mobile Overlay */}
+      {isMobileMenuOpen && (
+        <div 
+          className="lg:hidden fixed inset-0 bg-black bg-opacity-50 z-40"
+          onClick={() => setIsMobileMenuOpen(false)}
+        />
+      )}
+
       {/* Left Sidebar */}
-      <div className="w-64 shadow-lg" style={{ backgroundColor: 'var(--bg-secondary)', borderRight: '1px solid var(--border)' }}>
+      <div className={`
+        fixed lg:static inset-y-0 left-0 z-50 w-64 shadow-lg transform transition-transform duration-300 ease-in-out
+        ${isMobileMenuOpen ? 'translate-x-0' : '-translate-x-full lg:translate-x-0'}
+      `} style={{ backgroundColor: 'var(--bg-secondary)', borderRight: '1px solid var(--border)' }}>
         <div className="p-4 h-full flex flex-col">
-          <div className="flex items-center mb-8">
+          {/* Mobile Close Button */}
+          <div className="lg:hidden flex justify-between items-center mb-4">
+            <div className="flex items-center">
+              <div className="w-10 h-10 logo-container mr-3">
+                <span className="text-white font-bold text-sm">TCG</span>
+              </div>
+              <h1 className="text-xl font-bold" style={{ color: 'var(--text-primary)' }}>TCG Vault</h1>
+            </div>
+            <button
+              onClick={() => setIsMobileMenuOpen(false)}
+              className="p-2 rounded-lg"
+              style={{ color: 'var(--text-secondary)' }}
+            >
+              <svg className="h-6 w-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
+              </svg>
+            </button>
+          </div>
+
+          {/* Desktop Header */}
+          <div className="hidden lg:flex items-center mb-8">
             <div className="w-10 h-10 logo-container mr-3">
               <span className="text-white font-bold text-sm">TCG</span>
             </div>
@@ -110,6 +153,7 @@ export default function Layout({ children, user = { email: 'me@randallstillwell.
                     backgroundColor: item.active ? 'var(--bg-tertiary)' : 'transparent',
                     color: item.active ? 'var(--text-primary)' : 'var(--text-secondary)'
                   }}
+                  onClick={() => setIsMobileMenuOpen(false)}
                 >
                   <div className="flex items-center">
                     <span className="mr-3">{getIcon(item.icon)}</span>
@@ -178,6 +222,7 @@ export default function Layout({ children, user = { email: 'me@randallstillwell.
                       backgroundColor: item.active ? 'var(--bg-tertiary)' : 'transparent',
                       color: item.active ? 'var(--text-primary)' : 'var(--text-secondary)'
                     }}
+                    onClick={() => setIsMobileMenuOpen(false)}
                   >
                     <span className="mr-3">{getIcon(item.icon)}</span>
                     <span className="text-sm font-medium">{item.name}</span>
@@ -190,7 +235,7 @@ export default function Layout({ children, user = { email: 'me@randallstillwell.
       </div>
 
       {/* Main Content */}
-      <div className="flex-1 flex flex-col">
+      <div className="flex-1 flex flex-col lg:ml-0">
         {/* Top Header - Only show search on dashboard */}
         {showSearch && (
           <header className="p-6" style={{ backgroundColor: 'var(--bg-secondary)', borderBottom: '1px solid var(--border)' }}>

pages/cards.js

@@ -816,8 +816,19 @@ export default function Cards() {
           </div>
         ) : (
           <>
-            <div className={viewMode === 'grid' ? 'card-grid-container grid grid-cols-1 xs:grid-cols-2 sm:grid-cols-3 md:grid-cols-4 lg:grid-cols-3 xl:grid-cols-4 2xl:grid-cols-5 gap-4 sm:gap-6 lg:gap-8 p-4 sm:p-6 lg:p-8 lg:pr-96' : 'space-y-4 p-6'}>
+            <div className={viewMode === 'grid' ? 'card-grid-container grid grid-cols-2 sm:grid-cols-3 md:grid-cols-4 lg:grid-cols-3 xl:grid-cols-4 2xl:grid-cols-5 gap-3 sm:gap-4 lg:gap-6 p-3 sm:p-4 lg:p-6 xl:p-8 lg:pr-96' : 'space-y-4 p-6'}>
-              {cards.map(card => (
+              {cards.map((card, index) => {
+                // Calculate cards per row based on current breakpoint
+                const getCardsPerRow = () => {
+                  if (window.innerWidth >= 1536) return 5; // 2xl
+                  if (window.innerWidth >= 1280) return 4; // xl
+                  if (window.innerWidth >= 1024) return 3; // lg
+                  if (window.innerWidth >= 768) return 4;  // md
+                  if (window.innerWidth >= 640) return 3;  // sm
+                  return 2; // base
+                };
+
+                return (
                   <CardItem
                     key={card.id}
                     card={card}
@@ -828,8 +839,11 @@ export default function Cards() {
                     onAddToDeck={handleBulkAddToDeck}
                     onToggleFavorite={handleToggleFavorite}
                     isFavorited={favoritedCards.has(card.id)}
+                    cardIndex={index}
+                    cardsPerRow={getCardsPerRow()}
                   />
-              ))}
+                );
+              })}
             </div>
             
             {/* Infinite Scroll Loading Indicator */}