text:             const balls = document.getElementsByClassName('ball');
  document.onmousemove = (event) => {
    const x = (event.clientX * 100) / window.innerWidth + '%';
    const y = (event.clientY * 100) / window.innerHeight + '%';
  
              for (let i = 0; i < 2; i++) {
      balls[i].style.left = x;
      balls[i].style.top = y;
      balls[i].transform = 'translate(-' + x + ',-' + y + ')';
    }
  };