diff --git a/webui/static/style.css b/webui/static/style.css
index 432bc341..ac2efa01 100644
--- a/webui/static/style.css
+++ b/webui/static/style.css
@@ -108,7 +108,10 @@ body {
     position: fixed;
     pointer-events: none;
     border-radius: 50%;
-    filter: blur(40px);
+    /* The radial-gradient already fades to transparent at 70%, so a smaller blur
+       still reads as a soft aura — but shrinks the composited (orb + feather)
+       bounding box and the blur work. 40px -> 28px: ~imperceptible, cheaper fill. */
+    filter: blur(28px);
     will-change: transform, opacity;
 }
 
@@ -317,8 +320,11 @@ body.reduce-effects .sidebar::after {
        accent-gradient top now read as a soft blur instead of bleeding through
        sharply. (Only visible where the background is translucent — the opaque
        base toward the bottom still stops any bleed.) */
-    backdrop-filter: blur(28px) saturate(1.3);
-    -webkit-backdrop-filter: blur(28px) saturate(1.3);
+    /* Backdrop blur is re-evaluated whenever content drifts behind it (the
+       ambient orbs do). Cost scales with radius — 28px -> 18px keeps the frosted
+       read while cutting the per-frame blur work by ~a third. */
+    backdrop-filter: blur(18px) saturate(1.3);
+    -webkit-backdrop-filter: blur(18px) saturate(1.3);
 
     /* Subtle inner glow */
     box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);