Fix hero scroll - use fixed padding so content stays in place

app/layouts/topnav.vue

@@ -238,6 +238,7 @@ const { headerOffset, isCollapsed } = useScrollCollapse(100)
 // Hero scroll for home page
 const {
   heroHeight,
+  heroBaseHeight,
   collapseProgress,
   isCollapsed: heroIsCollapsed,
   collapsedHeight
@@ -332,11 +333,11 @@ const heroStyle = computed(() => {
 
 // Main content padding-top to compensate for fixed header
 // For catalog section: no padding - map extends behind header
-// Home page: hero height (dynamic)
+// Home page: FIXED at base height (not dynamic!) so content doesn't move with scroll
 // 154px = MainNav + SubNav (orders, seller, settings)
 const mainStyle = computed(() => {
   if (isCatalogSection.value) return { paddingTop: '0' }
-  if (isHomePage.value) return { paddingTop: `${heroHeight.value}px` }
+  if (isHomePage.value) return { paddingTop: `${heroBaseHeight.value}px` }
   return { paddingTop: '154px' }
 })