feat: add js to check height and decide if to top is required

assets/js/appearance.js

@@ -38,7 +38,22 @@ if (document.documentElement.getAttribute("data-auto-appearance") === "true") {
   });
 }
 
+function add_to_top_elem() {
+  var body = document.body,
+    html = document.documentElement;
+
+  const height = Math.max(
+    body.scrollHeight,
+    body.offsetHeight,
+    html.clientHeight,
+    html.scrollHeight,
+    html.offsetHeight
+  ) - 150;
+  document.getElementById("to-top").hidden = height < window.innerHeight;
+}
+
 window.addEventListener("DOMContentLoaded", (event) => {
+  add_to_top_elem();
   var switchers = document.querySelectorAll("[id^='appearance-switcher']");
   switchers.forEach((switcher) => {
     switcher.addEventListener("click", () => {