Order State Machine

{
  "nodes": [
    { "id": "p", "type": "ellipse", "label": "Pending",   "x": 40,  "y": 160, "fill": "#fef3c7" },
    { "id": "a", "type": "rect",    "label": "Paid",      "x": 220, "y": 160, "fill": "#dbeafe" },
    { "id": "s", "type": "rect",    "label": "Shipped",   "x": 400, "y": 160, "fill": "#ede9fe" },
    { "id": "d", "type": "ellipse", "label": "Delivered", "x": 580, "y": 160, "fill": "#dcfce7" },
    { "id": "c", "type": "rect",    "label": "Cancelled", "x": 220, "y": 300, "fill": "#fee2e2" },
    { "id": "r", "type": "rect",    "label": "Refunded",  "x": 400, "y": 300, "fill": "#fee2e2" }
  ],
  "edges": [
    { "id": "e1", "source": "p", "target": "a", "label": "pay" },
    { "id": "e2", "source": "a", "target": "s", "label": "ship" },
    { "id": "e3", "source": "s", "target": "d", "label": "deliver" },
    { "id": "e4", "source": "p", "target": "c", "label": "cancel" },
    { "id": "e5", "source": "a", "target": "r", "label": "refund" }
  ]
}