diff --git a/frontend/src/components/ThumbnailImage.tsx b/frontend/src/components/ThumbnailImage.tsx
index c97a71a..0b1007a 100644
--- a/frontend/src/components/ThumbnailImage.tsx
+++ b/frontend/src/components/ThumbnailImage.tsx
@@ -51,8 +51,8 @@ export default function ThumbnailImage({ checksum, fallbackIcon, downloadToken,
       <div 
         className={`flex items-center justify-center overflow-hidden ${docStyle}`}
         style={docType === 'sheets' ? {
-          backgroundImage: 'linear-gradient(to right, #f3f4f6 1px, transparent 1px), linear-gradient(to bottom, #f3f4f6 1px, transparent 1px)',
-          backgroundSize: '16px 16px',
+          backgroundImage: 'linear-gradient(to right, #e5e7eb 1px, transparent 1px), linear-gradient(to bottom, #e5e7eb 1px, transparent 1px)',
+          backgroundSize: '8px 4px',
           backgroundPosition: 'left top'
         } : {}}
       >