diff --git a/Block/ExpressCheckout/AbstractExpressCheckoutBlock.php b/Block/ExpressCheckout/AbstractExpressCheckoutBlock.php
index 3a1a386..c353d13 100644
--- a/Block/ExpressCheckout/AbstractExpressCheckoutBlock.php
+++ b/Block/ExpressCheckout/AbstractExpressCheckoutBlock.php
@@ -46,6 +46,12 @@ abstract class AbstractExpressCheckoutBlock extends Template
      * @var string|null
      */
     private ?string $state = null;
+    /**
+     * Memoized merchant-configured button style blob for the current request.
+     *
+     * @var string|null
+     */
+    private ?string $buttonStyle = null;
 
     /**
      * @param ScopeResolverInterface $scopeResolver
@@ -109,6 +115,18 @@ public function getUnavailableMessage(): string
         return (string)__('SeQura is not available for your account.');
     }
 
+    /**
+     * The merchant-configured button style blob, forwarded verbatim to the checkout library.
+     *
+     * @return string|null
+     */
+    public function getButtonStyle(): ?string
+    {
+        $this->resolveState();
+
+        return $this->buttonStyle;
+    }
+
     /**
      * The storefront solicit URL the CDN-library button fetches (GET, raw HTML response).
      *
@@ -161,7 +179,7 @@ private function resolveState(): string
                 ? (string)$this->shippingResolver->getResolvableShippingCountry($quote)
                 : '';
 
-            $this->state = $this->availabilityEvaluator->evaluate(
+            $result = $this->availabilityEvaluator->evaluate(
                 (string)$this->_storeManager->getStore()->getId(),
                 $this->getExpressCheckoutPage(),
                 $isLoggedIn,
@@ -172,6 +190,9 @@ private function resolveState(): string
                 $this->getCartCategoryIds($quote)
             );
 
+            $this->state = $result['state'];
+            $this->buttonStyle = $result['buttonStyle'];
+
             return $this->state;
         } catch (Exception $e) {
             Logger::logError('Checking Express Checkout availability failed: ' . $e->getMessage() .
diff --git a/Block/ExpressCheckout/ProductPage.php b/Block/ExpressCheckout/ProductPage.php
index 86e17d2..93626c3 100644
--- a/Block/ExpressCheckout/ProductPage.php
+++ b/Block/ExpressCheckout/ProductPage.php
@@ -58,6 +58,12 @@ class ProductPage extends Template
      * @var string|null
      */
     private ?string $state = null;
+    /**
+     * Memoized merchant-configured button style blob for the current request.
+     *
+     * @var string|null
+     */
+    private ?string $buttonStyle = null;
     /**
      * Memoized product for the current request (null also means "resolved to nothing").
      *
@@ -109,6 +115,18 @@ public function isAvailable(): bool
         return $this->resolveState() === AvailabilityEvaluator::STATE_BUTTON;
     }
 
+    /**
+     * The merchant-configured button style blob, forwarded verbatim to the checkout library.
+     *
+     * @return string|null
+     */
+    public function getButtonStyle(): ?string
+    {
+        $this->resolveState();
+
+        return $this->buttonStyle;
+    }
+
     /**
      * The viewed product's entity ID, for the JS controller.
      *
@@ -171,7 +189,7 @@ private function resolveState(): string
 
             // Always the guest (customer-agnostic) evaluation: the page is full-page cached, so
             // the session is depersonalized during render and the HTML is shared by all shoppers.
-            $this->state = $this->availabilityEvaluator->evaluate(
+            $result = $this->availabilityEvaluator->evaluate(
                 (string)$this->_storeManager->getStore()->getId(),
                 ExpressCheckoutPage::product()->getPage(),
                 false,
@@ -182,6 +200,9 @@ private function resolveState(): string
                 $this->getProductCategoryIds($product)
             );
 
+            $this->state = $result['state'];
+            $this->buttonStyle = $result['buttonStyle'];
+
             return $this->state;
         } catch (Exception $e) {
             Logger::logError('Checking Express Checkout availability for product failed: ' . $e->getMessage() .
diff --git a/Model/ExpressCheckout/AvailabilityEvaluator.php b/Model/ExpressCheckout/AvailabilityEvaluator.php
index d12bd62..415bacb 100644
--- a/Model/ExpressCheckout/AvailabilityEvaluator.php
+++ b/Model/ExpressCheckout/AvailabilityEvaluator.php
@@ -48,7 +48,7 @@ class AvailabilityEvaluator
      * @param string[] $productIds Product entity IDs in context.
      * @param string[] $categoryIds Category IDs in context.
      *
-     * @return string One of self::STATE_*.
+     * @return array{state: string, buttonStyle: string|null} State is one of self::STATE_*.
      */
     public function evaluate(
         string $storeId,
@@ -59,7 +59,7 @@ public function evaluate(
         string $ipAddress,
         array $productIds,
         array $categoryIds
-    ): string {
+    ): array {
         try {
             if ($isLoggedIn) {
                 /** @var ExpressCheckoutAvailabilityResponse $response */
@@ -73,31 +73,38 @@ public function evaluate(
                         $categoryIds
                     )
                 );
-
-                $available = $response->isSuccessful() && !empty($response->toArray()['available']);
-
-                return $available ? self::STATE_BUTTON : self::STATE_MESSAGE;
+                $unavailableState = self::STATE_MESSAGE;
+            } else {
+                /** @var GuestExpressCheckoutAvailabilityResponse $response */
+                $response = CheckoutAPI::get()->expressCheckout($storeId)->isAvailableForGuest(
+                    new GuestExpressCheckoutAvailabilityRequest(
+                        $page,
+                        $currency,
+                        $ipAddress,
+                        $productIds,
+                        $categoryIds
+                    )
+                );
+                $unavailableState = self::STATE_HIDDEN;
             }
 
-            /** @var GuestExpressCheckoutAvailabilityResponse $response */
-            $response = CheckoutAPI::get()->expressCheckout($storeId)->isAvailableForGuest(
-                new GuestExpressCheckoutAvailabilityRequest(
-                    $page,
-                    $currency,
-                    $ipAddress,
-                    $productIds,
-                    $categoryIds
-                )
-            );
+            $data = $response->toArray();
+            $buttonStyle = $data['buttonStyle'] ?? null;
 
-            return ($response->isSuccessful() && !empty($response->toArray()['available']))
-                ? self::STATE_BUTTON
-                : self::STATE_HIDDEN;
+            return [
+                'state' => ($response->isSuccessful() && !empty($data['available']))
+                    ? self::STATE_BUTTON
+                    : $unavailableState,
+                'buttonStyle' => is_string($buttonStyle) ? $buttonStyle : null,
+            ];
         } catch (Exception $e) {
             Logger::logError('Checking Express Checkout availability failed: ' . $e->getMessage() .
                 ' Trace: ' . $e->getTraceAsString());
 
-            return self::STATE_HIDDEN;
+            return [
+                'state' => self::STATE_HIDDEN,
+                'buttonStyle' => null,
+            ];
         }
     }
 }
diff --git a/composer.json b/composer.json
index 5adae92..dd0abe3 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
     "prefer-stable": true,
     "require": {
         "php": ">=7.4 <8.6",
-        "sequra/integration-core": "v5.5.0",
+        "sequra/integration-core": "v5.7.0",
         "ext-json": "*"
     },
     "autoload": {
diff --git a/view/frontend/templates/express/cart.phtml b/view/frontend/templates/express/cart.phtml
index 2dc818e..eecd308 100644
--- a/view/frontend/templates/express/cart.phtml
+++ b/view/frontend/templates/express/cart.phtml
@@ -3,9 +3,13 @@
 /** @var \Magento\Framework\Escaper $escaper */
 
 if ($block->isAvailable()):
+    $buttonStyle = (string)$block->getButtonStyle();
     ?>
     <div class="sequra-express-checkout" data-role="sequra-express-checkout">
         <div class="sequra-express-checkout-button"
+             <?php if ($buttonStyle !== ''): ?>
+             data-button-style="<?= $escaper->escapeHtmlAttr($buttonStyle); ?>"
+             <?php endif; ?>
              data-url="<?= $escaper->escapeHtmlAttr($block->getSolicitUrl()); ?>"></div>
     </div>
     <script type="text/x-magento-init">
diff --git a/view/frontend/templates/express/minicart.phtml b/view/frontend/templates/express/minicart.phtml
index c1e85fa..356ad23 100644
--- a/view/frontend/templates/express/minicart.phtml
+++ b/view/frontend/templates/express/minicart.phtml
@@ -3,6 +3,7 @@
 /** @var \Magento\Framework\Escaper $escaper */
 
 if ($block->isAvailable()):
+    $buttonStyle = (string)$block->getButtonStyle();
     ?>
     <?php // data-mage-init (not x-magento-init): the markup is re-injected by the Knockout
           // mini-cart on every `cart` section refresh, and only attribute-form init re-runs
@@ -12,6 +13,9 @@ if ($block->isAvailable()):
          data-mage-init='{"Sequra_Core/js/express/cart-express": {}}'
          data-availability-url="<?= $escaper->escapeHtmlAttr($block->getAvailabilityUrl()); ?>">
         <div class="sequra-express-checkout-button"
+             <?php if ($buttonStyle !== ''): ?>
+             data-button-style="<?= $escaper->escapeHtmlAttr($buttonStyle); ?>"
+             <?php endif; ?>
              data-url="<?= $escaper->escapeHtmlAttr($block->getSolicitUrl()); ?>"></div>
     </div>
     <?php
diff --git a/view/frontend/templates/express/product.phtml b/view/frontend/templates/express/product.phtml
index bd57c67..d991654 100644
--- a/view/frontend/templates/express/product.phtml
+++ b/view/frontend/templates/express/product.phtml
@@ -4,11 +4,15 @@
 
 if ($block->isAvailable()):
     $solicitUrl = $block->getProductSolicitUrl() . '?product=' . $block->getProductId() . '&qty=1';
+    $buttonStyle = (string)$block->getButtonStyle();
     ?>
     <div class="sequra-express-checkout sequra-express-checkout--product sequra-express-checkout--disabled"
          data-role="sequra-express-checkout-product">
         <div class="sequra-express-checkout-button"
              data-amount="0"
+             <?php if ($buttonStyle !== ''): ?>
+             data-button-style="<?= $escaper->escapeHtmlAttr($buttonStyle); ?>"
+             <?php endif; ?>
              data-url="<?= $escaper->escapeHtmlAttr($solicitUrl); ?>"></div>
     </div>
     <script type="text/x-magento-init">