classDef for circle and elipse

A node and D node should be green.

graph LR; A((start))-->B(step1); B-->C[step2]; C-->D{step3}; D-->D2(-step3.5-); D2-->E[end]; classDef green fill:#9f6,stroke:#333,stroke-width:1px; class A,B,C,D,D2,E green;