diff --git a/CHANGES.md b/CHANGES.md
index 9ffab37056e1cf72a68e1906696d832dfbb24249..4d2691aef771e114b9210ad7bd0f6c24a75c0cb2 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -6,6 +6,7 @@ Changes
 
 ### Unreleased
 
+* 2021-02-05 - Bugfix: Moodle core Back-to-top button was not clickable over Boost Campus footer
 * 2021-02-05 - Move Moodle Plugin CI from Travis CI to Github actions
 
 ### Release v3.10-r2
diff --git a/scss/post.scss b/scss/post.scss
index 0a6233094a4ad15098054a1f3853d74e150b851b..5c19d47bcb0ca1067eaadeef2b3d9d85c8419148 100644
--- a/scss/post.scss
+++ b/scss/post.scss
@@ -930,7 +930,14 @@ a[href^="mailto"]::before {
   Additional Elements
   -------------------------------------*/
 
-/* Back to top button */
+/* Moodle Core Back to top button */
+body.scrolled #goto-top-link {
+    /* For unknown reasons, the Moodle Core Back to top button is made unclickable by the Boost Campus footer.
+       We fix this by simply raising the z-index of the button. */
+    z-index: $zindex-tooltip;
+}
+
+/* Boost Campus Back to top button */
 #back-to-top {
     display: none;
     position: fixed;