reading the documentation https://mermaid.js.org/syntax/entityRelationshipDiagram.html#config-options

How is this style config applied? I would like to style the following diagram:

erDiagram
    CAR ||--o{ NAMED-DRIVER : allows
    CAR {
        string registrationNumber
        string make
        string model
    }
    PERSON ||--o{ NAMED-DRIVER : is
    PERSON {
        string firstName
        string lastName
        int age
    }

Explicitly I would like to color the registrationNumber. How is this possible using the fill option indicated in the documentation?

Here a link to the live editor:
Mermaid Live Example

THX