{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Sales by region, per-cell theme override",
  "data": {
    "name": "samples",
    "values": [
      {"region": "NA", "sales": 120},
      {"region": "EU", "sales": 95},
      {"region": "APAC", "sales": 140}
    ]
  },
  "facet": {
    "column": {"field": "region", "type": "nominal"},
    "cell_overrides": [
      {"row": 0, "column": 0, "theme": {"marks": {"bar": {"fill": "#e11d48"}}}},
      {"row": 0, "column": 1, "theme": {"marks": {"bar": {"fill": "#16a34a"}}}}
    ]
  },
  "spec": {
    "$schema": "urn:prism:schema:v1:spec",
    "mark": "bar",
    "encoding": {
      "x": {"field": "region", "type": "nominal"},
      "y": {"field": "sales", "type": "quantitative"}
    }
  }
}