Toastr color doesn't change even when I have it in my CSS

Question

I have the following in my scripts.js

toastr.options = {
    "closeButton": false,
    "debug": false,
    "newestOnTop": false,
    "progressBar": false,
    "positionClass": "toast-bottom-full-width",
    "preventDuplicates": false,
    "onclick": null,
    "showDuration": "300",
    "hideDuration": "1000",
    "timeOut": "0",
    "extendedTimeOut": "1000",
    "showEasing": "swing",
    "hideEasing": "linear",
    "showMethod": "fadeIn",
    "hideMethod": "fadeOut"
    }
    toastr.info(`Right Number ${rightGuessString}. Game Over.`);

and in my CSS

.toast-info {
  background-color: rgb(140, 71, 71);
}

However, this doesn't work. The toast always displays blue. What am I missing?