diff --git a/ui/src/hooks/useTheme.ts b/ui/src/hooks/useTheme.ts
index 8306c2f..f364a84 100644
--- a/ui/src/hooks/useTheme.ts
+++ b/ui/src/hooks/useTheme.ts
@@ -48,7 +48,7 @@ export const THEMES: ThemeOption[] = [
     id: 'business',
     name: 'Business',
     description: 'Deep navy (#000e4e) and gray monochrome',
-    previewColors: { primary: '#000e4e', background: '#faf8f5', accent: '#6b7280' }
+    previewColors: { primary: '#000e4e', background: '#eaecef', accent: '#6b7280' }
   }
 ]
 
diff --git a/ui/src/styles/globals.css b/ui/src/styles/globals.css
index 09f4380..e927b54 100644
--- a/ui/src/styles/globals.css
+++ b/ui/src/styles/globals.css
@@ -598,8 +598,8 @@
 
 .theme-business {
   --radius: 0.5rem;
-  /* Warm off-white background */
-  --background: oklch(0.9800 0.0040 85);
+  /* Concrete-like blue-gray background */
+  --background: oklch(0.9500 0.0080 265);
   /* Deep navy foreground #000e4e */
   --foreground: oklch(0.1700 0.0900 265);
   /* White cards with shadow depth */
@@ -631,7 +631,7 @@
   --chart-3: oklch(0.5000 0.0400 265);
   --chart-4: oklch(0.6500 0.0200 265);
   --chart-5: oklch(0.8000 0.0100 265);
-  --sidebar: oklch(0.9600 0.0030 85);
+  --sidebar: oklch(0.9300 0.0100 265);
   --sidebar-foreground: oklch(0.1700 0.0900 265);
   --sidebar-primary: oklch(0.1700 0.0900 265);
   --sidebar-primary-foreground: oklch(1.0000 0 0);