finish file server

static/dist/support.js

@@ -0,0 +1,10 @@
+document.querySelector("main").addEventListener("scroll", () => {
+  const links = document.querySelectorAll(".tab-link");
+  links.forEach((element) => element.removeAttribute("active"));
+
+  const pageWidth = document.querySelector("main > article").offsetWidth;
+  const scroll = document.querySelector("main").scrollLeft;
+  const currentPage = Math.round(scroll / pageWidth);
+
+  if (links[currentPage]) links[currentPage].setAttribute("active", "");
+});