const totalSeconds = Math.floor(diff / 1000);
const hours = Math.floor(totalSeconds / 3600);
const minutes = Math.floor((totalSeconds % 3600) / 60);
const seconds = totalSeconds % 60;
countdownEl.innerHTML =
`${hours.toString().padStart(2, '0')}:` +
`${minutes.toString().padStart(2, '0')}:` +
`${seconds.toString().padStart(2, '0')}`;
}
setInterval(updateCountdown, 1000);
updateCountdown();
