{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/column-formatting.schema.json",
  "elmType": "div",
  "txtContent": "@currentField",
  "attributes": {
    "class": {
      "operator": "?",
      "operands": [
        {
          "operator": "<=",
          "operands": [
            "[$DueDate]",
            "@now"
          ]
        },
        "ms-fontColor-redDark ms-fontWeight-semibold",
        ""
      ]
    }
  }
}