Implement dynamic page size for mobile devices and optimize rendering with content visibility

Web/templates/main.html

@@ -724,7 +724,9 @@
     // Add this line to define allItems globally
     let allItems = [];
 
-    const MAIN_ITEMS_PAGE_SIZE = 120;
+    // Dynamic page size: scan viewport/screen size to only load the exact amount needed.
+    const isMobileDevice = window.matchMedia('(max-width: 768px)').matches;
+    const MAIN_ITEMS_PAGE_SIZE = isMobileDevice ? 20 : 120;
     let mainItemsNextOffset = 0;
     let mainItemsHasMore = false;
     let mainItemsLoadingMore = false;
@@ -781,10 +783,10 @@
             styles.flexDirection === 'column';
 
         const distanceToEnd = isMobileLayout
-            ? itemsContainer.scrollHeight - (itemsContainer.scrollTop + itemsContainer.clientHeight)
+            ? Math.max(document.body.scrollHeight, document.documentElement.scrollHeight) - (window.scrollY + window.innerHeight)
             : itemsContainer.scrollWidth - (itemsContainer.scrollLeft + itemsContainer.clientWidth);
         const prefetchThreshold = isMobileLayout
-            ? Math.max(220, itemsContainer.clientHeight * 0.9)
+            ? window.innerHeight * 1.5
             : Math.max(260, itemsContainer.clientWidth * 1.4);
         if (distanceToEnd > prefetchThreshold) {
             return;
@@ -1167,6 +1169,7 @@
 
         if (!mainItemsScrollPrefetchBound) {
             itemsContainer.addEventListener('scroll', maybePrefetchMainItems, { passive: true });
+            window.addEventListener('scroll', maybePrefetchMainItems, { passive: true });
             mainItemsScrollPrefetchBound = true;
         }
 
@@ -1188,7 +1191,7 @@
                 updateMainItemsLoadingIndicator();
             });
         }, {
-            root: itemsContainer,
+            root: isMobileLayout ? null : itemsContainer,
             threshold: 0.15,
             rootMargin: isMobileLayout ? '0px 0px 900px 0px' : '0px 900px 0px 0px'
         });
@@ -3561,6 +3564,9 @@
             margin: 0 !important;
             padding: 15px !important;
             scroll-snap-align: none !important;
+            /* Only render when user looks at it (content-visibility virtualizes the DOM) */
+            content-visibility: auto;
+            contain-intrinsic-size: auto 300px;
         }
         
         .item-card:hover {

Web/templates/main_admin.html

@@ -1612,6 +1612,9 @@
             margin: 0 !important;
             padding: 15px !important;
             scroll-snap-align: none !important;
+            /* Only render when user looks at it (content-visibility virtualizes the DOM) */
+            content-visibility: auto;
+            contain-intrinsic-size: auto 300px;
         }
         
         .item-card:hover {
@@ -3339,7 +3342,9 @@ document.addEventListener('DOMContentLoaded', ()=>{
     });
 
     // Function to load items from server
-    const MAIN_ADMIN_ITEMS_PAGE_SIZE = 120;
+    // Dynamic page size: scan viewport/screen size to only load the exact amount needed.
+    const isMobileDevice = window.matchMedia('(max-width: 768px)').matches;
+    const MAIN_ADMIN_ITEMS_PAGE_SIZE = isMobileDevice ? 20 : 120;
     let mainAdminItemsNextOffset = 0;
     let mainAdminItemsHasMore = false;
     let mainAdminItemsLoadingMore = false;
@@ -3397,10 +3402,10 @@ document.addEventListener('DOMContentLoaded', ()=>{
             styles.flexDirection === 'column';
 
         const distanceToEnd = isMobileLayout
-            ? itemsContainer.scrollHeight - (itemsContainer.scrollTop + itemsContainer.clientHeight)
+            ? Math.max(document.body.scrollHeight, document.documentElement.scrollHeight) - (window.scrollY + window.innerHeight)
             : itemsContainer.scrollWidth - (itemsContainer.scrollLeft + itemsContainer.clientWidth);
         const prefetchThreshold = isMobileLayout
-            ? Math.max(220, itemsContainer.clientHeight * 0.9)
+            ? window.innerHeight * 1.5
             : Math.max(260, itemsContainer.clientWidth * 1.4);
         if (distanceToEnd > prefetchThreshold) {
             return;
@@ -3772,6 +3777,7 @@ document.addEventListener('DOMContentLoaded', ()=>{
 
         if (!mainAdminItemsScrollPrefetchBound) {
             itemsContainer.addEventListener('scroll', maybePrefetchMainAdminItems, { passive: true });
+            window.addEventListener('scroll', maybePrefetchMainAdminItems, { passive: true });
             mainAdminItemsScrollPrefetchBound = true;
         }
 
@@ -3793,7 +3799,7 @@ document.addEventListener('DOMContentLoaded', ()=>{
                 updateMainAdminItemsLoadingIndicator();
             });
         }, {
-            root: itemsContainer,
+            root: isMobileLayout ? null : itemsContainer,
             threshold: 0.15,
             rootMargin: isMobileLayout ? '0px 0px 900px 0px' : '0px 900px 0px 0px'
         });