Diagram Color Convention#

Diagrams are used to summarize relationships, dependencies, and lifecycle flows that are easier to understand visually than through text alone. To make these diagrams easier to understand, colors are also used to distinguish the role of each element, such as the primary entity, related entities, contextual configuration, optional objects, and lifecycle states.

The diagram below illustrates the standard role-based palette used for entity relationship diagrams:

flowchart LR
  E["Primary entity"]:::entity
  B["Business Data"]:::business
  L["Linked entity"]:::linked
  N["Non-Business Data"]:::nonbusiness
  C["Context / configuration"]:::context
  O["Optional object"]:::optional

  E --- B
  E --- L
  B --- N
  C --- E
  O --- E

  classDef entity fill:#FB9F53,stroke:#FB9F53,color:#000
  classDef business fill:#65CDE8,stroke:#65CDE8,color:#000
  classDef linked fill:#FCD5B5,stroke:#FCD5B5,color:#000
  classDef nonbusiness fill:#B7DEE8,stroke:#B7DEE8,color:#000
  classDef context fill:#B9CDE5,stroke:#B9CDE5,color:#000
  classDef optional fill:#B7DEE8,stroke:#65CDE8,color:#000,stroke-width:1px,stroke-dasharray: 5 5

Table: Entity diagram labels and descriptions

Other diagram types use a different color convention. Instead of distinguishing entity roles, these diagrams use color to represent states within a State Model or lifecycle:

• Active or in‑progress states use the initial state color.
• Terminal or final states use the final state color.

The diagram below illustrates a simple lifecycle workflow, using the standard color convention to distinguish active states from terminal states:

graph TD
    A1[Created] -->|Enqueue| A2[Queued]

    A2 -->|Complete| A3[Completed]
    A2 -->|Cancel| A4[Canceled]

    classDef mermaid_initial_state fill:#d7e4bd,stroke:#92d050,stroke-width:3px,color:#000;
    classDef mermaid_final_state fill:#a7e2f2,stroke:#65CDE8,stroke-width:3px,color:#000;

    class A1,A2 mermaid_initial_state;
    class A3,A4 mermaid_final_state;