DayPicker days not clickable REACT

Question

I tried to use this react-day-picker component to pick a single day on my site but it is not clickable.

I took the code from https://react-day-picker.js.org/ and there they show the day is clickable I did not understand what I did wrong (i tried all their codes none is clickable )

this is the code I am using-

import React, { useState } from 'react';
import { DayPicker } from 'react-day-picker';

import { format } from 'date-fns';

export default function App() {
    const [selectedDay, setSelectedDay] = useState<Date>("");

    const footer = selectedDay
        ? `You selected ${format(selectedDay, 'PPP')}.`
        : `Please pick a day.`;

    return (
        <DayPicker
            mode="single"
            selected={selectedDay}
            onSelect={setSelectedDay}
            footer={footer}
        />
    );
}