diff --git a/apps/arc-web/app/app.css b/apps/arc-web/app/app.css
index b4ffa9f2b..eedf6c36a 100644
--- a/apps/arc-web/app/app.css
+++ b/apps/arc-web/app/app.css
@@ -29,10 +29,11 @@
 /* ── Background atmosphere ── */
 
 .bg-atmosphere {
-  background:
+  background-color: var(--color-navy-950);
+  background-image:
     radial-gradient(ellipse 120% 60% at 15% 5%, rgba(53, 127, 158, 0.12) 0%, transparent 50%),
-    radial-gradient(ellipse 80% 50% at 85% 90%, rgba(90, 200, 168, 0.07) 0%, transparent 45%),
-    var(--color-navy-950);
+    radial-gradient(ellipse 80% 50% at 85% 90%, rgba(90, 200, 168, 0.07) 0%, transparent 45%);
+  background-attachment: fixed;
 }
 .bg-atmosphere::before {
   content: "";