Some further dark-mode fixes, added toggle to homepage

- Homepage toggle especially useful for not-logged-in users since they
do not have a dropdown.

resources/sass/_lists.scss

@@ -581,6 +581,8 @@ ul.pagination {
     @include lightDark(color, #555, #eee);
     fill: currentColor;
     white-space: nowrap;
+    line-height: 1.6;
+    cursor: pointer;
     &:hover, &:focus {
       text-decoration: none;
       background-color: var(--color-primary-light);