@startuml
' convert it with additional command line argument -DRELATIVE_INCLUDE="." to use locally
!if %variable_exists("RELATIVE_INCLUDE")
  !include ./../C4_Context.puml
!else
  !include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml
!endif

LAYOUT_WITH_LEGEND()

title System Context diagram for Internet Banking System

Person(customer, "Personal Banking Customer", "A customer of the bank, with personal bank accounts.")
System(banking_system, "Internet Banking System", "Allows customers to view information about their bank accounts, and make payments.")

System_Ext(mail_system, "E-mail system", "The internal Microsoft Exchange e-mail system.")
System_Ext(mainframe, "Mainframe Banking System", "Stores all of the core banking information about customers, accounts, transactions, etc.")

Rel(customer, banking_system, "Uses")
Rel_Back(customer, mail_system, "Sends e-mails to")
Rel_Neighbor(banking_system, mail_system, "Sends e-mails", "SMTP")
Rel(banking_system, mainframe, "Uses")
@enduml