diff --git a/src/components/cases/documents-tab.tsx b/src/components/cases/documents-tab.tsx
index c34d4ec..352b3e4 100644
--- a/src/components/cases/documents-tab.tsx
+++ b/src/components/cases/documents-tab.tsx
@@ -216,6 +216,23 @@ export function CaseDocumentsTab({ caseId }: { caseId: string }) {
     window.open(data.signedUrl, "_blank");
   };
 
+  const openPreview = async (doc: any) => {
+    setPreviewDoc(doc);
+    setPreviewUrl(null);
+    setPreviewLoading(true);
+    const { data, error } = await supabase.storage
+      .from("case-documents")
+      .createSignedUrl(doc.storage_path, 300);
+    setPreviewLoading(false);
+    if (error) { toast.error(error.message); setPreviewDoc(null); return; }
+    setPreviewUrl(data.signedUrl);
+  };
+
+  const closePreview = () => {
+    setPreviewDoc(null);
+    setPreviewUrl(null);
+  };
+
   const del = async (doc: any) => {
     if (!confirm(`Delete ${doc.name}?`)) return;
     await supabase.storage.from("case-documents").remove([doc.storage_path]);