diff --git a/packages/ckeditor5-mermaid/src/index.ts b/packages/ckeditor5-mermaid/src/index.ts
index 46c94ca0f..58fa30892 100644
--- a/packages/ckeditor5-mermaid/src/index.ts
+++ b/packages/ckeditor5-mermaid/src/index.ts
@@ -6,6 +6,7 @@ import insertMermaidIcon from './../theme/icons/insert.svg';
 import previewModeIcon from './../theme/icons/preview-mode.svg';
 import splitModeIcon from './../theme/icons/split-mode.svg';
 import sourceModeIcon from './../theme/icons/source-mode.svg';
+import "../theme/mermaid.css";
 
 export const icons = {
 	infoIcon,
diff --git a/packages/ckeditor5/src/plugins.ts b/packages/ckeditor5/src/plugins.ts
index edce9596b..aef2909f4 100644
--- a/packages/ckeditor5/src/plugins.ts
+++ b/packages/ckeditor5/src/plugins.ts
@@ -16,6 +16,8 @@ import Uploadfileplugin from "./plugins/file_upload/uploadfileplugin.js";
 import { Kbd } from "@triliumnext/ckeditor5-keyboard-marker";
 import { Mermaid } from "@triliumnext/ckeditor5-mermaid";
 
+import "@triliumnext/ckeditor5-mermaid/index.css";
+
 const TRILIUM_PLUGINS: typeof Plugin[] = [
     CutToNotePlugin,
     ItalicAsEmPlugin,