diff --git a/packages/mermaid/src/diagram-api/types.ts b/packages/mermaid/src/diagram-api/types.ts
index ab82e7e74..67730e33c 100644
--- a/packages/mermaid/src/diagram-api/types.ts
+++ b/packages/mermaid/src/diagram-api/types.ts
@@ -83,4 +83,4 @@ export type HTML = d3.Selection<HTMLIFrameElement, unknown, Element, unknown>;
 
 export type SVG = d3.Selection<SVGSVGElement, unknown, Element, unknown>;
 
-export type getDiagramStyles = (options?: unknown) => string;
+export type getDiagramStyles = (options?: any) => string;