diff --git a/tutorials/mdbook/mermaid.md b/tutorials/mdbook/mermaid.md
index 00aa3e7..89dca2c 100644
--- a/tutorials/mdbook/mermaid.md
+++ b/tutorials/mdbook/mermaid.md
@@ -1,30 +1,31 @@
-
-editor see https://mermaid.live/
-
-## example for mindmap
-
-```mermaid
-mindmap
-  root((mindmap))
-    Origins
-      Long history
-      ::icon(fa fa-book)
-      Popularisation
-        British popular psychology author Tony Buzan
-    Research
-      On effectivness<br/>and features
-      On Automatic creation
-        Uses
-            Creative techniques
-            Strategic planning
-            Argument mapping
-    Tools
-      Pen and paper
-      Mermaid
-```
-
-## plugin required in visual studio
-
-- vscode-mermaid-syntax-highlight
-- Markdown All in One
+
+editor see https://mermaid.live/
+
+## example for mindmap
+
+```mermaid
+mindmap
+  root((mindmap))
+    Origins
+      Long history
+      ::icon(fa fa-book)
+      Popularisation
+        British popular psychology author Tony Buzan
+    Research
+      On effectivness<br/>and features
+      On Automatic creation
+        Uses
+            Creative techniques
+            Strategic planning
+            Argument mapping
+    Tools
+      Pen and paper
+      Mermaid
+      MdBooks
+```
+
+## plugin required in visual studio
+
+- vscode-mermaid-syntax-highlight
+- Markdown All in One
 - Markdown Preview Enhanced
\ No newline at end of file