In the initial page, currently, it has Press Enter to Begin Press E to Edit List.
It should have something to indicate the amount of item in the list before user enters the randomization. Like Press Enter to Begin Press E to Edit List (123)
Currently, for no-cookie mode, when the list is depleted, hitting enter will not bring back the initial list. So the users will have no choice but to reload the page and put in the list again.
Simplest approach would be just store the list to class property when the users put in the list. And use this to bring the list back to state after depletion.
Currently, when the list is be randomized, the display just displaying number 0-999 randomly.
I would be nicer if the random display actually shows what's being randomized.