diff --git a/components/email/reader-attachments.tsx b/components/email/reader-attachments.tsx
index 95f3b54e4..fcd29b2ec 100644
--- a/components/email/reader-attachments.tsx
+++ b/components/email/reader-attachments.tsx
@@ -268,7 +268,7 @@ export function ReaderAttachments<T extends ReaderAttachmentItem>({
 
       <div className={cn(
         "grid",
-        layout === "cards" ? "grid-cols-[repeat(auto-fill,minmax(10rem,1fr))] gap-3" : "grid-cols-[repeat(auto-fill,minmax(15rem,1fr))] gap-2",
+        layout === "cards" ? "grid-cols-[repeat(auto-fill,minmax(10rem,1fr))] gap-3" : "grid-cols-[repeat(auto-fill,minmax(min(100%,20rem),1fr))] gap-2",
       )}>
         {shown.map((attachment) => (
           <div key={attachment.id} className="flex min-w-0 flex-col gap-1">