diff --git a/src/typings.d.ts b/src/typings.d.ts
index ef3a206eed..70d99ca3f4 100644
--- a/src/typings.d.ts
+++ b/src/typings.d.ts
@@ -15,4 +15,4 @@ declare var NGRX_RUNTIME_CHECKS: boolean;
 
 declare var PWA_VERSION: string;
 
-declare var THEME: boolean;
+declare var THEME: string;