How can I please change the background color of a desktop application using JavaScript so that the settings are saved after the program is closed? I am using ElectronJS and since it is a desktop application, I cannot use cookies for this purpose.

Application example

What I've tried:

const color1Picker = document.getElementById("confirmColors")
color1Picker.onclick = () => {
  const color1 = document.getElementById("color1").value;
  const color2 = document.getElementById("color2").value;
  document.querySelector(":root").style.setProperty('--color1', color1);
}

Here I expected this solution to work only until the user exits the application.

What solution can I think of?

Somehow (probably using NodeJS/Express) save the variables from HTML into a JSON file and then reload them into Vanilla JS using fetch.

But this seems like too clumsy a solution to me.

Can you think of a better way please?