diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8e873cc..0f9a80a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,8 @@ All notable changes to the New Optic website will be documented in this file.
 ### Changed
 
 - Optimized mobile rendering by disabling heavy blur, fixed backgrounds, ambient animations, and WebGL glass below desktop widths.
+- Changed mobile CSS to reference only the compressed mobile background by default, keeping the full PNG desktop-only.
+- Added mobile `content-visibility` containment so offscreen sections do less rendering work on low-end devices.
 - Reworked collection cards from abstract placeholders to image-led product cards.
 - Improved dark-section heading contrast.
 - Corrected French typography and accents.
diff --git a/app/globals.css b/app/globals.css
index 401777f..b2d2c26 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -20,10 +20,8 @@ body {
   margin: 0;
   min-height: 100vh;
   background:
-    linear-gradient(180deg, rgba(251, 250, 248, 0.86) 0%, rgba(246, 245, 242, 0.92) 45%, rgba(255, 255, 255, 0.94) 100%),
-    url('/assets/New-optic-BG.png') center top / cover fixed,
-    radial-gradient(circle at top left, rgba(49, 95, 143, 0.13), transparent 34rem),
-    radial-gradient(circle at 82% 12%, rgba(216, 221, 229, 0.9), transparent 24rem),
+    linear-gradient(180deg, rgba(251, 250, 248, 0.9) 0%, rgba(246, 245, 242, 0.94) 45%, rgba(255, 255, 255, 0.96) 100%),
+    url('/assets/New-optic-BG-mobile.webp') center top / cover scroll,
     linear-gradient(180deg, #fbfaf8 0%, #f6f5f2 42%, #ffffff 100%);
   color: var(--ink);
   font-family: var(--font-sans), system-ui, sans-serif;
@@ -137,13 +135,6 @@ a {
 }
 
 @media (max-width: 1023px) {
-  body {
-    background:
-      linear-gradient(180deg, rgba(251, 250, 248, 0.9) 0%, rgba(246, 245, 242, 0.94) 45%, rgba(255, 255, 255, 0.96) 100%),
-      url('/assets/New-optic-BG-mobile.webp') center top / cover scroll,
-      linear-gradient(180deg, #fbfaf8 0%, #f6f5f2 42%, #ffffff 100%);
-  }
-
   body::before,
   body::after {
     display: none;
@@ -164,6 +155,20 @@ a {
     background: rgba(255, 255, 255, 0.86);
     box-shadow: 0 10px 30px rgba(17, 19, 23, 0.07);
   }
+
+  main > section {
+    content-visibility: auto;
+    contain-intrinsic-size: 1px 780px;
+  }
+
+  main > section:first-child {
+    content-visibility: visible;
+    contain-intrinsic-size: auto;
+  }
+
+  * {
+    transition-duration: 160ms !important;
+  }
 }
 
 @media (max-width: 767px) {
@@ -172,3 +177,14 @@ a {
     box-shadow: 0 10px 24px rgba(17, 19, 23, 0.08) !important;
   }
 }
+
+@media (min-width: 1024px) {
+  body {
+    background:
+      linear-gradient(180deg, rgba(251, 250, 248, 0.86) 0%, rgba(246, 245, 242, 0.92) 45%, rgba(255, 255, 255, 0.94) 100%),
+      url('/assets/New-optic-BG.png') center top / cover fixed,
+      radial-gradient(circle at top left, rgba(49, 95, 143, 0.13), transparent 34rem),
+      radial-gradient(circle at 82% 12%, rgba(216, 221, 229, 0.9), transparent 24rem),
+      linear-gradient(180deg, #fbfaf8 0%, #f6f5f2 42%, #ffffff 100%);
+  }
+}