Scroll Progress Bar with gsap

HTML at start of <body>

<progress max="100" value="0"></progress>

CSS

progress {
  position: fixed;
  top: 0;
  left: 0;
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 15px;
  border: none;
  background: transparent;
  z-index: 99999;
}
progress::-webkit-progress-bar {
  background: transparent;
}
progress::-webkit-progress-value {
  background: linear-gradient(to left, #db38b5,#01b3e3,#25ce7b,#fdc741,#ff6b01,#fc4236);
  background-attachment: fixed;
}
progress::-moz-progress-bar {
  background: linear-gradient(to left, #db38b5,#01b3e3,#25ce7b,#fdc741,#ff6b01,#fc4236);
  background-attachment: fixed;
}

gsap JS

gsap.registerPlugin(ScrollTrigger);

gsap.to('progress', {
  value: 100,
  ease: 'none',
  scrollTrigger: { scrub: 0.8 }
});