Optimize styles for plantuml

plantuml/plantuml.config

@@ -1,4 +1,27 @@
-skinparam linetype ortho
-skinparam monochrome true
 scale 1.5
-skinparam dpi 300
+skinparam dpi 300
+skinparam padding 5
+skinparam nodesep 60
+skinparam ranksep 80
+<style>
+root {
+  FontName "Noto Sans Regular"
+  FontSize 14
+  RoundCorner 10
+  LineThickness 1.5
+  BackGroundColor transparent
+}
+arrow {
+  Color #666666
+  LineThickness 2
+}
+wbsDiagram {
+  Linecolor darkgray
+  arrow {
+    LineColor darkgray
+  }
+}
+</style>
+skinparam handwritten false
+skinparam shadowing false
+skinparam linetype ortho