use much, much simpler logic for adding anchors to h[2-4] elements

assets/js/src/anchor.js

@@ -1,7 +1,23 @@
-import SimpleAnchor from "simple-anchor";
+// Heavily inspired by AnchorJS: https://github.com/bryanbraun/anchorjs
 
-const anchors = new SimpleAnchor({
-  icon: null,
+// loop through each h2, h3, h4 in this page's content area
+document.querySelectorAll(["div#content h2", "div#content h3", "div#content h4"]).forEach((h) => {
+  // don't add to elements without a pre-existing ID (e.g. `<h2 id="...">`)
+  if (!h.hasAttribute("id")) {
+    return;
+  }
+
+  // build the anchor link (the "#" icon is added via CSS)
+  const anchor = document.createElement("a");
+  anchor.className = "anchorjs-link";
+  anchor.href = `#${h.getAttribute("id")}`;
+
+  // if this is a touchscreen, always show the "#" icon instead waiting for hover
+  // NOTE: this is notoriously unreliable; see https://github.com/Modernizr/Modernizr/pull/2432
+  if ("ontouchstart" in window) {
+    anchor.style.opacity = "1";
+  }
+
+  // add anchor link to the right of the heading
+  h.appendChild(anchor);
 });
-
-anchors.add("div#content h2, div#content h3, div#content h4");