fix: update flowchart style

Author: nutkiattisak

2619. array-prototype-last/README.md

@@ -1,6 +1,13 @@
 ```mermaid
 flowchart TD
-    A(Start) --> B{Is array empty?}
-    B -- No --> C(Return last element)
-    B -- Yes --> D(Return -1)
+    A(Start) --> B{Is array empty ?}
+    B -- No --> C[Return last element]
+    B -- Yes --> D[Return -1]
+    C & D --> E(End)
+
+    style A fill:#52bc94,stroke:#ffffff,stroke-width:1px,color: #ffffff
+    style B fill:#ffb020,stroke:#ffffff,stroke-width:1px,color: #ffffff
+    style C fill:#101841,stroke:#ffffff,stroke-width:1px,color: #ffffff
+    style D fill:#101841,stroke:#ffffff,stroke-width:1px,color: #ffffff
+    style E fill:#d14243,stroke:#ffffff,stroke-width:1px,color: #ffffff
 ```