text: 
  
  const container = document.querySelector('body');
  const highlight = document.getElementById('highlight');
  var containerHeight;
  
  
  
  window.onscroll = function (){
    containerHeight = container.offsetHeight - window.innerHeight;
  
    containerPos = container.getBoundingClientRect();
  
    diff = containerHeight + containerPos.top;
  
    progressPercentage = diff / containerHeight * 100;
    
    cssWidth = Math.floor(100 - progressPercentage)
  
    highlight.style.width = cssWidth + "%";
  };