/* Hide all countries in the dropdown */
select[name="location_[country]"] option {
  display: none;
}

/* Explicitly show US and Canada */
select[name="location_[country]"] option[value="United States"],
select[name="location_[country]"] option[value="Canada"] {
  display: block;
}

/* Ensure the default "Select a country" option is visible */
select[name="location_[country]"] option[value=""] {
  display: block;
}