{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Actual vs benchmark",
  "datasets": {
    "actual": {
      "values": [
        {"day": "2026-01-01", "score": 0.40},
        {"day": "2026-01-02", "score": 0.51}
      ]
    },
    "benchmark": {
      "values": [
        {"day": "2026-01-01", "score": 0.50},
        {"day": "2026-01-02", "score": 0.50}
      ]
    }
  },
  "layer": [
    {
      "$schema": "urn:prism:schema:v1:spec",
      "data": {"name": "actual"},
      "mark": {"type": "line", "stroke": "#3366cc"},
      "encoding": {
        "x": {"field": "day",   "type": "temporal"},
        "y": {"field": "score", "type": "quantitative"}
      }
    },
    {
      "$schema": "urn:prism:schema:v1:spec",
      "data": {"name": "benchmark"},
      "mark": {"type": "line", "stroke": "#999999", "stroke_dash": [4, 2]},
      "encoding": {
        "x": {"field": "day",   "type": "temporal"},
        "y": {"field": "score", "type": "quantitative"}
      }
    }
  ]
}