book.json

{
  "structure": {
    "readme": "Introduction.md"
  },
  "pdf": {
    "fontSize": 12
  },
  "variables": {
    "should": "<span style=\"color:darkgoldenrod;font-weight:bold\">Should:</span>",
    "could": "<span style=\"color:green;font-weight:bold\">Could:</span>",
    "must": "<span style=\"color:red;font-weight:bold\">Must:</span>"
  },
  "plugins": [
    "structured-toc",
    "restructure-navigation",
    "anchors"
  ],
  "pluginsConfig": {
    "structured-toc": {},
    "gitbook-restructure-navigation": {
      "transformations": [
        {
          "from": 0,
          "to": 1
        }
      ]
    }
  }
}