text: const durationInput = document.querySelector('#duration');
  const startButton = document.querySelector('#start');
  const pauseButton = document.querySelector('#pause');
  const circle = document.querySelector('circle');
  
  const perimeter = circle.getAttribute('r') * 2 * Math.PI;
  circle.setAttribute('stroke-dasharray', perimeter);
  
  let duration;
  
  const timer = new Timer(durationInput, startButton, pauseButton, {
    onStart(totalDuration) {
      duration = totalDuration;
    },
    onTick(timeRemaining) {
      circle.setAttribute(
        'stroke-dashoffset',
        (perimeter * timeRemaining) / duration - perimeter
      );
    },
    onComplete() {
      circle.setAttribute('stroke-dashoffset', 0);
      durationInput.value = duration;
    },
  });
  