How to code JSON beautifully in c#

I want the code to look beautiful but have Bugphobia .
Let me explain my fear:I am afraid to add wired spaces to break my code I want a convention to help me make it look nice without breaking it.
this is  post request of the real code where I changed the secret fields to pseudo fields .
look how beautiful the JavaScript looks like but it's deceiving as i am going to transform all VALUES into variables later (json does not like variables).
Here is the javascript (which looks good ):

var data = JSON.stringify({
  "fields": {
    "horse_colour": "brown",
    "birth_date": "2011",
    "sire_name": "sire name",
    "dam_name": "dam name"
  }
});

var xhr = new XMLHttpRequest();
xhr.withCredentials = true;

xhr.addEventListener("readystatechange", function () {
  if (this.readyState === this.DONE) {
    console.log(this.responseText);
  }
});

xhr.open("POST", "https://breeding-portal.mystagingwebsite.com/wp-json/acf/v3/listings/726");
xhr.setRequestHeader("authorization", "Basic bG93ZXNhbGV4QGdtYWlsLmNvbTpNYXJ0eW1jZmx5MTIz");
xhr.setRequestHeader("content-type", "application/json");

xhr.send(data);

This is a working C# code using RESTSHARP (which I am looking for a pretty way to organise it READY FOR VARIABLES.(the values).

var client = new RestClient("https://breeding-portal.mystagingwebsite.com/wp-json/acf/v3/listings/726");
var request = new RestRequest(Method.POST);
request.AddHeader("authorization", "Basic bG93ZXNhbGV4QGdtYWlsLmNvbTpNYXJ0eW1jZmx5MTIz");
request.AddHeader("content-type", "application/json");
request.AddParameter("application/json", "\t{\n  \"fields\": {\n\t\t\"horse_colour\":\"brown\",\n\t\t\"birth_date\":\"2011\",\n\t\t\"sire_name\":\"sire name\",\n\t\t\"dam_name\":\"dam name\"\n  }\n}\n", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);