I wanna add a class that makes a button looks disabled with calssList.add, I'm having hard time snice yesterday with this since i can't see any difference on the button, even if i see in the inspector that the button is having the css class that i wanna add, it doesn't make any changes.

###js

if (numberCheckboxChecked >= 3 && selectedLayout=='Layout1') {
  alert("You can't have more than two articles in this layout");
  saveButton.disabled = true;
  saveButton.classList.add("fl-button-disabled");

css

.fl-settings-save.fl-button.fl-button-large.fl-button-disabled{
  pointer-events: none;
  color: #666666;
  background-color: gray;
  border: 1px solid gray;
}