progressive enhancement for collection filter pills

Flex-wrap base (no JS needed, active pill always visible). JS hook
switches to horizontal scroll with scroll-into-view when pills exceed
2.5 rows on mobile. Desktop always wraps.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/css/theme-semantic.css

@@ -206,19 +206,66 @@
   }
 }
 
-/* Horizontal scroll fade hint for collection category pills (mobile only) */
+/* Collection filter pills — flex-wrap base, JS-enhanced scroll on mobile */
-.collection-filter-scroll {
+.collection-filter-pills {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.375rem;
+}
+
+.collection-filter-pill {
+  display: inline-block;
+  padding: 0.375rem 0.75rem;
+  border-radius: 9999px;
+  font-size: 0.75rem;
+  white-space: nowrap;
+  transition: opacity 0.15s;
+  background-color: var(--t-surface-raised);
+  color: var(--t-text-primary);
+
+  &.active {
+    background-color: var(--t-accent);
+    color: var(--t-text-on-accent);
+    font-weight: 500;
+  }
+}
+
+/* When JS detects overflow, it adds this class to switch to horizontal scroll */
+.collection-filters.is-scrollable {
+  overflow-x: auto;
+  scrollbar-width: none;
+  -webkit-overflow-scrolling: touch;
   mask-image: linear-gradient(to right, black calc(100% - 2rem), transparent);
   -webkit-mask-image: linear-gradient(to right, black calc(100% - 2rem), transparent);
-  scrollbar-width: none;
 
   &::-webkit-scrollbar {
     display: none;
   }
 
+  & .collection-filter-pills {
+    flex-wrap: nowrap;
+  }
+}
+
 @media (min-width: 640px) {
+  .collection-filter-pills {
+    gap: 0.5rem;
+  }
+
+  .collection-filter-pill {
+    padding: 0.5rem 1rem;
+    font-size: 0.875rem;
+  }
+
+  /* Desktop always wraps — no scroll needed */
+  .collection-filters.is-scrollable {
+    overflow-x: visible;
     mask-image: none;
     -webkit-mask-image: none;
+
+    & .collection-filter-pills {
+      flex-wrap: wrap;
+    }
   }
 }
 

assets/js/app.js

@@ -458,10 +458,39 @@ const SearchModal = {
   }
 }
 
+// Flex-wrap base → horizontal scroll enhancement for collection category pills.
+// If the pills wrap past 2 rows on mobile, switches to single-row scroll
+// and scrolls the active pill into view.
+const CollectionFilters = {
+  mounted() { this._enhance() },
+  updated() { this._enhance() },
+  _enhance() {
+    const nav = this.el
+    const ul = nav.querySelector("ul")
+    if (!ul) return
+
+    // Reset to measure natural wrap height
+    nav.classList.remove("is-scrollable")
+    const firstItem = ul.querySelector("li")
+    if (!firstItem) return
+
+    const rowHeight = firstItem.offsetHeight
+    const wrapsToMany = ul.scrollHeight > rowHeight * 2.5
+
+    if (wrapsToMany && window.innerWidth < 640) {
+      nav.classList.add("is-scrollable")
+      const active = nav.querySelector("[aria-current]")
+      if (active) {
+        active.scrollIntoView({ inline: "center", block: "nearest", behavior: "instant" })
+      }
+    }
+  }
+}
+
 const csrfToken = document.querySelector("meta[name='csrf-token']").getAttribute("content")
 const liveSocket = new LiveSocket("/live", Socket, {
   params: {_csrf_token: csrfToken},
-  hooks: {...colocatedHooks, ColorSync, Lightbox, CartPersist, CartDrawer, ProductImageScroll, SearchModal},
+  hooks: {...colocatedHooks, ColorSync, Lightbox, CartPersist, CartDrawer, ProductImageScroll, SearchModal, CollectionFilters},
 })
 
 // Show progress bar on live navigation and form submits

lib/simpleshop_theme_web/live/shop/collection.ex

@@ -137,57 +137,44 @@ defmodule SimpleshopThemeWeb.Shop.Collection do
     <div class="flex flex-wrap items-center justify-between gap-3 mb-6">
       <nav
         aria-label="Collection filters"
-        class="collection-filter-scroll overflow-x-auto py-1 -mx-4 px-4 sm:overflow-visible sm:mx-0 sm:px-0 sm:py-0"
+        id="collection-filters"
+        phx-hook="CollectionFilters"
+        class="collection-filters"
       >
-        <ul class="flex gap-1.5 sm:flex-wrap sm:gap-2">
+        <ul class="collection-filter-pills">
-          <li class="shrink-0">
+          <li>
             <.link
               navigate={collection_path("all", @current_sort)}
+              aria-current={@current_slug == nil && "page"}
               class={[
-                "px-3 py-1.5 sm:px-4 sm:py-2 rounded-full text-xs sm:text-sm whitespace-nowrap transition-colors",
+                "collection-filter-pill",
-                if(@current_slug == nil, do: "font-medium", else: "hover:opacity-80")
+                if(@current_slug == nil, do: "active", else: "hover:opacity-80")
               ]}
-              style={
-                if(@current_slug == nil,
-                  do: "background-color: var(--t-accent); color: var(--t-text-on-accent);",
-                  else: "background-color: var(--t-surface-raised); color: var(--t-text-primary);"
-                )
-              }
             >
               All
             </.link>
           </li>
-          <li class="shrink-0">
+          <li>
             <.link
               navigate={collection_path("sale", @current_sort)}
+              aria-current={@current_slug == "sale" && "page"}
               class={[
-                "px-3 py-1.5 sm:px-4 sm:py-2 rounded-full text-xs sm:text-sm whitespace-nowrap transition-colors",
+                "collection-filter-pill",
-                if(@current_slug == "sale", do: "font-medium", else: "hover:opacity-80")
+                if(@current_slug == "sale", do: "active", else: "hover:opacity-80")
               ]}
-              style={
-                if(@current_slug == "sale",
-                  do: "background-color: var(--t-accent); color: var(--t-text-on-accent);",
-                  else: "background-color: var(--t-surface-raised); color: var(--t-text-primary);"
-                )
-              }
             >
               Sale
             </.link>
           </li>
           <%= for category <- @categories do %>
-            <li class="shrink-0">
+            <li>
               <.link
                 navigate={collection_path(category.slug, @current_sort)}
+                aria-current={@current_slug == category.slug && "page"}
                 class={[
-                  "px-3 py-1.5 sm:px-4 sm:py-2 rounded-full text-xs sm:text-sm whitespace-nowrap transition-colors",
+                  "collection-filter-pill",
-                  if(@current_slug == category.slug, do: "font-medium", else: "hover:opacity-80")
+                  if(@current_slug == category.slug, do: "active", else: "hover:opacity-80")
                 ]}
-                style={
-                  if(@current_slug == category.slug,
-                    do: "background-color: var(--t-accent); color: var(--t-text-on-accent);",
-                    else: "background-color: var(--t-surface-raised); color: var(--t-text-primary);"
-                  )
-                }
               >
                 {category.name}
               </.link>