diff --git a/parfum-shop/src/components/ProductDetailPage.css b/parfum-shop/src/components/ProductDetailPage.css
index 3f8b3f3..8822a96 100644
--- a/parfum-shop/src/components/ProductDetailPage.css
+++ b/parfum-shop/src/components/ProductDetailPage.css
@@ -5,6 +5,15 @@
   background: var(--theme-bg);
 }
 
+.detail-body-grid {
+  display: grid;
+  grid-template-columns: 1fr;
+}
+
+.detail-sections {
+  min-width: 0;
+}
+
 .eyebrow,
 .label-title {
   font-size: var(--text-xs);
@@ -195,24 +204,13 @@
 }
 
 .product-purchase-panel {
-  position: relative;
-  grid-column: 10 / -1;
-  grid-row: 1;
-  z-index: 4;
-  justify-self: end;
-  align-self: center;
-  width: min(100%, 390px);
-  max-height: none;
-  overflow: visible;
   display: flex;
   flex-direction: column;
   gap: clamp(1rem, 1.8vw, 1.45rem);
+  width: 100%;
   padding: 0;
   border: 0;
   background: transparent;
-  backdrop-filter: none;
-  -webkit-backdrop-filter: none;
-  box-shadow: none;
 }
 
 .purchase-price-row {
@@ -919,6 +917,36 @@
   line-height: 1.45;
 }
 
+@media (min-width: 1024px) {
+  .detail-body-grid {
+    grid-template-columns: 1fr clamp(280px, 24vw, 390px);
+    grid-template-rows: auto 1fr;
+    column-gap: var(--gap-lg);
+  }
+
+  .product-hero {
+    grid-column: 1 / -1;
+    grid-row: 1;
+  }
+
+  .detail-sidebar {
+    grid-column: 2;
+    grid-row: 1 / 3;
+    z-index: 4;
+    padding-top: clamp(10rem, 24svh, 18rem);
+  }
+
+  .detail-sections {
+    grid-column: 1;
+    grid-row: 2;
+  }
+
+  .product-purchase-panel {
+    position: sticky;
+    top: clamp(5rem, 8vw, 6.5rem);
+  }
+}
+
 @media (max-width: 1180px) {
   .product-story-grid,
   .product-meta-section,
@@ -943,13 +971,9 @@
     padding-bottom: clamp(2.5rem, 5vw, 4rem);
   }
 
-  .product-media-column,
-  .product-purchase-panel {
+  .product-media-column {
     grid-column: 1;
     grid-row: auto;
-  }
-
-  .product-media-column {
     min-height: 0;
     display: grid;
     grid-template-columns: 1fr;
@@ -1021,13 +1045,9 @@
   }
 
   .product-purchase-panel {
-    justify-self: stretch;
-    align-self: auto;
     width: min(100%, 46rem);
     max-width: 46rem;
-    max-height: none;
     margin-inline: auto;
-    overflow: visible;
     gap: var(--gap-sm);
   }
 }
@@ -1046,8 +1066,7 @@
     padding-bottom: clamp(1.5rem, 5vw, 2.5rem);
   }
 
-  .product-media-column,
-  .product-purchase-panel {
+  .product-media-column {
     grid-column: 1;
     grid-row: auto;
   }
@@ -1230,6 +1249,66 @@
   }
 }
 
+.mobile-purchase-cta {
+  display: none;
+}
+
+@media (max-width: 1023px) {
+  .detail-body-grid {
+    padding-bottom: clamp(4rem, 8vw, 5.5rem);
+  }
+
+  .mobile-purchase-cta {
+    position: fixed;
+    bottom: 0;
+    left: 0;
+    right: 0;
+    z-index: 500;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: var(--gap-sm);
+    padding: clamp(0.6rem, 1.8vw, 0.85rem) var(--page-x);
+    background: color-mix(in srgb, var(--theme-bg) 88%, transparent);
+    border-top: 1px solid var(--theme-border);
+    backdrop-filter: blur(18px) saturate(1.2);
+    -webkit-backdrop-filter: blur(18px) saturate(1.2);
+    transform: translateY(100%);
+    transition: transform var(--duration-med) var(--ease-out);
+  }
+
+  .mobile-purchase-cta.is-visible {
+    transform: translateY(0);
+  }
+
+  .mobile-purchase-info {
+    display: flex;
+    flex-direction: column;
+    gap: 0.15rem;
+    min-width: 0;
+  }
+
+  .mobile-purchase-info span {
+    color: var(--theme-text-muted);
+    font-size: var(--text-xs);
+    letter-spacing: 0.12em;
+    text-transform: uppercase;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+
+  .mobile-purchase-info strong {
+    color: var(--theme-text);
+    font-size: var(--text-lg);
+    font-weight: 400;
+  }
+
+  .mobile-purchase-cta .atmos-btn {
+    flex-shrink: 0;
+  }
+}
+
 @media (prefers-reduced-motion: reduce) {
   .is-transition-arriving .product-hero-image,
   .is-transition-arriving [data-product-transition-reveal] {
diff --git a/parfum-shop/src/components/ProductDetailPage.jsx b/parfum-shop/src/components/ProductDetailPage.jsx
index be9c5b3..5222816 100644
--- a/parfum-shop/src/components/ProductDetailPage.jsx
+++ b/parfum-shop/src/components/ProductDetailPage.jsx
@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 import { Link, useParams } from "react-router";
 import perfumes from "../data/perfumes";
 import SharedNavbar from "./SharedNavbar";
@@ -166,17 +166,7 @@ function ProductPurchasePanel({
   );
 }
 
-function ProductHero({
-  perfume,
-  selectedImage,
-  setSelectedImage,
-  selectedSize,
-  setSelectedSize,
-  selectedPriceCents,
-  discountPreviewCents,
-  addToCart,
-  subscribeToProduct,
-}) {
+function ProductHero({ perfume, selectedImage, setSelectedImage }) {
   const galleryImages = [...new Set([perfume.image, ...(perfume.gallery || [])])].slice(0, 3);
 
   return (
@@ -229,15 +219,6 @@ function ProductHero({
         </div>
       </div>
 
-      <ProductPurchasePanel
-        perfume={perfume}
-        selectedSize={selectedSize}
-        setSelectedSize={setSelectedSize}
-        selectedPriceCents={selectedPriceCents}
-        discountPreviewCents={discountPreviewCents}
-        addToCart={addToCart}
-        subscribeToProduct={subscribeToProduct}
-      />
     </section>
   );
 }
@@ -550,6 +531,33 @@ function ProductRecommendations({ currentSlug, startProductTransition }) {
   );
 }
 
+function MobilePurchaseCTA({ perfume, selectedSize, addToCart, visible }) {
+  const selectedProductId = `${perfume.slug}-${selectedSize === "sample" ? "sample" : "full"}`;
+  const selectedProductLabel = selectedSize === "sample" ? "Probe" : "50 ml Flakon";
+
+  return (
+    <div className={`mobile-purchase-cta ${visible ? "is-visible" : ""}`}>
+      <div className="mobile-purchase-info">
+        <span>{perfume.name}</span>
+        <strong>{perfume.prices[selectedSize]}</strong>
+      </div>
+      <button
+        className="atmos-btn atmos-btn--primary atmos-btn--uppercase"
+        type="button"
+        onClick={() =>
+          addToCart(
+            selectedProductId,
+            1,
+            `${perfume.name} ${selectedProductLabel} wurde in den Warenkorb gelegt.`
+          ).catch(() => {})
+        }
+      >
+        Kaufen
+      </button>
+    </div>
+  );
+}
+
 function ProductDetailContent({ perfumeSlug }) {
   const { addToCart, subscribeToProduct, user } = useShop();
   const { activeSlug, phase, startProductTransition } = useProductTransition();
@@ -565,6 +573,8 @@ function ProductDetailContent({ perfumeSlug }) {
   const [selectedSize, setSelectedSize] = useState("full");
   const [showReviewDetails, setShowReviewDetails] = useState(false);
   const [commentPage, setCommentPage] = useState(0);
+  const sidebarRef = useRef(null);
+  const [isPanelVisible, setIsPanelVisible] = useState(true);
   const selectedPriceCents = priceToCents(perfume.prices[selectedSize]);
   const sampleCredit = user?.sampleCredits?.find(
     (credit) => credit.slug === perfume.slug && credit.status === "available"
@@ -621,6 +631,17 @@ function ProductDetailContent({ perfumeSlug }) {
     return () => window.clearInterval(interval);
   }, [safeCommentPages.length]);
 
+  useEffect(() => {
+    const el = sidebarRef.current;
+    if (!el) return;
+    const observer = new IntersectionObserver(
+      ([entry]) => setIsPanelVisible(entry.isIntersecting),
+      { threshold: 0 }
+    );
+    observer.observe(el);
+    return () => observer.disconnect();
+  }, []);
+
   const productJsonLd = useMemo(() => buildProductJsonLd(perfume), [perfume]);
 
   return (
@@ -638,35 +659,52 @@ function ProductDetailContent({ perfumeSlug }) {
       <SharedNavbar variant="hero" brandMode="back" />
 
       <main id="main-content" className="shell">
-        <ProductHero
-          perfume={perfume}
-          selectedImage={selectedImage}
-          setSelectedImage={setSelectedImage}
-          selectedSize={selectedSize}
-          setSelectedSize={handleSizeSelection}
-          selectedPriceCents={selectedPriceCents}
-          discountPreviewCents={discountPreviewCents}
-          addToCart={addToCart}
-          subscribeToProduct={subscribeToProduct}
-        />
+        <div className="detail-body-grid">
+          <ProductHero
+            perfume={perfume}
+            selectedImage={selectedImage}
+            setSelectedImage={setSelectedImage}
+          />
 
-        <ProductStorySection perfume={perfume} />
-        <ProductStructureSection perfume={perfume} />
-        <ProductMetaSection perfume={perfume} />
-        <ProductReviews
-          reviewSummary={reviewSummary}
-          safeCommentPages={safeCommentPages}
-          commentPage={commentPage}
-          setCommentPage={setCommentPage}
-          showReviewDetails={showReviewDetails}
-          setShowReviewDetails={setShowReviewDetails}
-        />
-        <ProductTestingCTA perfume={perfume} addToCart={addToCart} />
-        <ProductRecommendations
-          currentSlug={perfume.slug}
-          startProductTransition={startProductTransition}
-        />
+          <div className="detail-sidebar" ref={sidebarRef}>
+            <ProductPurchasePanel
+              perfume={perfume}
+              selectedSize={selectedSize}
+              setSelectedSize={handleSizeSelection}
+              selectedPriceCents={selectedPriceCents}
+              discountPreviewCents={discountPreviewCents}
+              addToCart={addToCart}
+              subscribeToProduct={subscribeToProduct}
+            />
+          </div>
+
+          <div className="detail-sections">
+            <ProductStorySection perfume={perfume} />
+            <ProductStructureSection perfume={perfume} />
+            <ProductMetaSection perfume={perfume} />
+            <ProductReviews
+              reviewSummary={reviewSummary}
+              safeCommentPages={safeCommentPages}
+              commentPage={commentPage}
+              setCommentPage={setCommentPage}
+              showReviewDetails={showReviewDetails}
+              setShowReviewDetails={setShowReviewDetails}
+            />
+            <ProductTestingCTA perfume={perfume} addToCart={addToCart} />
+            <ProductRecommendations
+              currentSlug={perfume.slug}
+              startProductTransition={startProductTransition}
+            />
+          </div>
+        </div>
       </main>
+
+      <MobilePurchaseCTA
+        perfume={perfume}
+        selectedSize={selectedSize}
+        addToCart={addToCart}
+        visible={!isPanelVisible}
+      />
     </div>
   );
 }