add to cart button disabled when 0 stock and newsletter form theming

resources/views/product/show.blade.php

@@ -196,8 +196,13 @@ class="underline-slide font-semibold whitespace-nowrap"
                     @endif
                 @endforeach
 
+                @php
+                    // Same initial pick as product-form-controller.js's connect()
+                    // (?variant= or the first), so the button doesn't flip on load.
+                    $initialVariant = collect($variantsData)->firstWhere('id', (int) request('variant')) ?? ($variantsData[0] ?? null);
+                @endphp
                 <x-checkout::add-to-cart
-                    :purchasable="$variantsData[0]['id'] ?? null"
+                    :purchasable="$initialVariant['id'] ?? null"
                     :quantity="false"
                     class="flex flex-col gap-6"
                 >
@@ -207,7 +212,7 @@ class="flex flex-col gap-6"
 
                     <div class="flex items-stretch gap-10">
                         <x-ui.quantity name="quantity" />
-                        <x-ui.button type="submit" class="flex-1">{{ __('storefront.product.add_to_cart') }}</x-ui.button>
+                        <x-ui.button type="submit" class="flex-1" data-product-form-target="submit" :disabled="! ($initialVariant['inStock'] ?? true)">{{ __('storefront.product.add_to_cart') }}</x-ui.button>
                     </div>
                 </x-checkout::add-to-cart>