Change mermaid default background color

src/components/Mermaid.js

@@ -9,9 +9,8 @@ mermaid.initialize({
     textColor: 'rgb(0,0,0)',
     primaryBorderColor: 'rgb(87,87,87)',
     lineColor: 'rgb(87,87,87)',
-    mainBkg: 'rgb(125,193,204)',
+    mainBkg: 'rgb(255,200,25)',
     sequenceNumberColor: 'rgb(255,255,255)',
-
   }
 })