dotfiles

 1var scrollButton = document.querySelector(".scroll-back");
 2var rootElement = document.documentElement;
 3
 4if (scrollButton) {
 5  function handleScroll() {
 6    var scrollTotal = rootElement.scrollHeight - rootElement.clientHeight;
 7    if (rootElement.scrollTop / scrollTotal > 0.5) {
 8      scrollButton.style.visibility = "visible";
 9      scrollButton.style.opacity = 100;
10    } else {
11      scrollButton.style.visibility = "hidden";
12      scrollButton.style.opacity = 0;
13    }
14  }
15
16  function scrollBack() {
17    rootElement.scrollTo({
18      top: 0,
19      behavior: matchMedia("(prefers-reduced-motion: reduce)").matches
20        ? "instant"
21        : "smooth",
22    });
23  }
24
25  scrollButton.addEventListener("click", scrollBack);
26  document.addEventListener("scroll", handleScroll, { passive: true });
27}