Fix scrolling outside of content area

(cherry picked from commit 57c24d9b46f32a736974c1c57f9c63a7a1fb4660)

_static/css/custom.css

@@ -681,6 +681,7 @@ footer {
 .wy-body-for-nav {
     position: relative;
     background-color: var(--content-wrap-background-color);
+    overflow: visible;
 }
 
 @media only screen and (min-width: 769px) {