Make map fullscreen behind transparent navbar

app/layouts/topnav.vue

@@ -145,11 +145,14 @@ const headerStyle = computed(() => {
 })
 
 // Main content padding-top to compensate for fixed header
+// For catalog section: no padding - map extends behind header
 // 100px = MainNav with search (input + chips)
 // 154px = MainNav + SubNav (orders, seller, settings)
-const mainStyle = computed(() => ({
-  paddingTop: (isHomePage.value || isCatalogSection.value) ? '100px' : '154px'
-}))
+const mainStyle = computed(() => {
+  if (isCatalogSection.value) return { paddingTop: '0' }
+  if (isHomePage.value) return { paddingTop: '100px' }
+  return { paddingTop: '154px' }
+})
 
 // Provide collapsed state to child components (CatalogPage needs it for map positioning)
 provide('headerCollapsed', isHeaderCollapsed)