flowchart LR
  E0[(stage checkpoint)]:::ckpt --> E1["greedy generate"]:::model --> E2["extract_answer<br/>&lt;answer&gt;N&lt;/answer&gt;"]:::proc --> E3{"== gold?"}:::rl --> E4["GSM8K accuracy<br/>Base -> SFT -> ... -> GRPO"]:::eval

  classDef data fill:#cdeccd,stroke:#2e7d32,stroke-width:2px,color:#143d1a;
  classDef store fill:#cfeee9,stroke:#1f9e8f,stroke-width:2px,color:#0c3a34;
  classDef proc fill:#cfe3fb,stroke:#1565c0,stroke-width:2px,color:#0d2c52;
  classDef model fill:#ffe8a3,stroke:#d48806,stroke-width:2px,color:#5a3d00;
  classDef rl fill:#ffd9b3,stroke:#e67e22,stroke-width:2px,color:#6b3500;
  classDef loss fill:#ffd4d4,stroke:#c0392b,stroke-width:2px,color:#5c1212;
  classDef ckpt fill:#ececec,stroke:#666666,stroke-width:2px,color:#222222;
  classDef eval fill:#e7d6fb,stroke:#8e44ad,stroke-width:2px,color:#3d1a5a;
  classDef out fill:#e7d6fb,stroke:#7b3fbf,stroke-width:2px,color:#3d1a5a;
  classDef op fill:#ffffff,stroke:#888888,stroke-width:2px,color:#333333;