const root = document.documentElement;
let mouseX = 0;
let mouseY = 0;

document.addEventListener("mousemove", (evt) => {
  mouseX = evt.clientX / innerWidth;
  mouseY = evt.clientY / innerHeight;

  root.style.setProperty("--mouse-x", `${mouseX}`);
  root.style.setProperty("--mouse-y", `${mouseY}`);

  console.log(root.style.getPropertyValue("--mouse-x"));
});