{
  "params": {
    "span": {
      "type": "range",
      "min": 10,
      "max": 24,
      "step": 1,
      "default": 16,
      "label": "Span",
      "describe": "Clear span between the two landing towers in metres: 10 crosses a two-lane street, 16 a four-lane road, 24 a boulevard. Each landing adds 3 m and each staircase reaches about 11 m along the road."
    },
    "style": {
      "type": "choice",
      "options": [
        "steel",
        "concrete",
        "wooden"
      ],
      "default": "steel",
      "label": "Style",
      "describe": "steel (painted Warren truss sides, round columns, open steel stairs), concrete (deep box girder with solid parapets, square piers), wooden (timber beams, cross-braced railings, park or campus bridge)."
    },
    "roof": {
      "type": "toggle",
      "default": false,
      "label": "Roof",
      "describe": "Covered walkway: a curved canopy on steel, a flat slab on concrete, a gable roof on timber, with lights under it."
    },
    "paint": {
      "type": "choice",
      "options": [
        "teal",
        "blue",
        "red",
        "yellow",
        "grey"
      ],
      "default": "teal",
      "label": "Paint",
      "describe": "Accent colour for the steelwork, handrails and roof edge: teal, blue, red, yellow, grey."
    }
  },
  "presets": {
    "highway overpass": {
      "span": 24,
      "style": "concrete",
      "roof": true,
      "paint": "grey"
    },
    "park crossing": {
      "span": 12,
      "style": "wooden",
      "roof": true,
      "paint": "red"
    },
    "station skywalk": {
      "span": 18,
      "style": "steel",
      "roof": true,
      "paint": "blue"
    }
  },
  "night": {
    "lamp": {
      "zone": "lamp",
      "color": "#fff1cf",
      "intensity": 1.4,
      "describe": "Deck lamps and canopy lights glow."
    }
  }
}