Reset js countdown timer and keep it running on page refresh

Question

I want to update this code from here: Reset js countdown timer

to reset every 3 hours, but to also keep running when the user reloads the page - like if the user opens the page at 0:2:57:00 and the user refreshes the page in two minutes the countdown should show 0:2:55:00

Here is the code:

<script>
const second = 1000,
      minute = second * 60,
      hour = minute * 60,
      day = hour * 60;
let round = 1;
const diff = 180 ; // set timediff in minutes
//let countDown = new Date('Mar 19, 2022 22:28:00').getTime();
let countDown = new Date(new Date('Apr 1, 2022 18:04').getTime() + diff*60000);
let x = setInterval(function() {
  let now = new Date().getTime();
  let distance = countDown - now;
  if (distance < 0) {    
   const diff = 180
   
  }

  document.getElementById('days').innerText = Math.floor(distance / (day));
  document.getElementById('hours').innerText = Math.floor((distance % (day)) / (hour));
  document.getElementById('minutes').innerText = Math.floor((distance % (hour)) / (minute));
  document.getElementById('seconds').innerText = Math.floor((distance % (minute)) / second);
  
   document.getElementById('dayz').innerText = Math.floor(distance / (day));
  document.getElementById('hourz').innerText = Math.floor((distance % (day)) / (hour));
  document.getElementById('minutez').innerText = Math.floor((distance % (hour)) / (minute));
  document.getElementById('secondz').innerText = Math.floor((distance % (minute)) / second);
  
}, second)
</script>

I don't know how to fix it. I've searched all the internet!

Thank you very much for any help!