diff --git a/web/src/types/reader.d.ts b/web/src/types/reader.d.ts
index 0e72490..866c9a3 100644
--- a/web/src/types/reader.d.ts
+++ b/web/src/types/reader.d.ts
@@ -254,3 +254,10 @@ interface ProgressDisplay {
   label?: string;
   time_left?: string;
 }
+
+interface FoliateTocItem {
+  id: number;
+  label: string;
+  href: string;
+  subitems?: FoliateTocItem[];
+}