@startuml
skinparam backgroundColor #EEEBDC
skinparam sequenceArrowColor DeepSkyBlue
skinparam sequenceParticipantBorderColor DeepSkyBlue
skinparam sequenceActorBorderColor DeepSkyBlue
skinparam sequenceLifeLineBorderColor blue
actor User
participant "First Class" as A
participant "Second Class" as B
participant "Last Class" as C

User -> A: DoMoreWork
activate A
@enduml