scroll up button, visible class

src/css/style.css

@@ -409,6 +409,10 @@ a.button:visited {
     display: none;
 }
 
+.visible-block {
+    display: block;
+}
+
 .spoiler-text {
     display: inline;
     /* These are technically the same, but use both */

src/js/page-functions.js

@@ -17,11 +17,12 @@ function DetectPageScroll() {
 
     /* Maximum number of pixels that can be scrolled by the user */
     let scrollTotal = ROOT.scrollHeight - ROOT.clientHeight;
+    let scrollUpButton = document.querySelector(".scroll-up-button");
 
     if ((ROOT.scrollTop / scrollTotal) > 0.80) {
-        //show button
+        /* Show button */
     } else {
-        //hide button
+        /* Hide button */
     }
 }