{
  "type": "object",
  "required": ["color"],
  "additionalProperties": false,
  "properties": {
    "color": {
      "type": "string",
      "pattern": "^#(?:[0-9a-fA-F]{3}){1,2}$"
    },
    "top_label": { "type": "string" },
    "bottom_label": { "type": "string" }
  }
}