Mermaid
An example on the use of styling in Mermaid
graph TD
%%classDef
classDef classAlert fill:red,color:white,stroke-width:2px,stroke:darkRed
classDef classOk fill:green,color:#00FF00,stroke-width:2px,stroke:darkGreen
classDef classWarn fill:orange,color:#FF0,stroke-width:2px,stroke:darkOrange
%%flowchart
A[Default style] --> B[Alert style!]
A --> C[OK style!]
A --> D[Warning style!]
%%Style
class B classAlert
class C classOk
class D classWarn
Another example with link control
graph LR;
AF{AF}
U[U]
U--WI-->AF
U--NLP-->AF
linkStyle default fill:none,stroke:green,stroke-width:1px
linkStyle 1 fill:none,stroke:red,stroke-width:1px