[gtk/matthiasc/for-master] Adwaita: Don't do n-th child things for list rows

[Matthias Clasen <matthiasc src gnome org>]

commit bfe5b0d1b7a13749642a94a8a75fd82b6401a9ae
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Nov 11 13:07:31 2020 -0500

    Adwaita: Don't do n-th child things for list rows
    
    Making the list row child css depend on the position
    is very expensive, and does not acutally work correctly
    (since we don't have widgets for all children, so the
    position of the child widget does not reflect the actual
    model item position).
    
    To make this more palatable, use the bottom border
    instead of the top border, since most lists have a natural
    border at the top (with headers), and may end up with
    empty space at the bottom.

 gtk/theme/Adwaita/_common.scss | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index a552965cdd..8b5c53bdec 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -3098,13 +3098,13 @@ list {
   > row.expander { padding: 0px; }
   > row.expander .row-header { padding: 2px; }
 
-  &.horizontal row.separator:not(:first-child),
-  &.separators.horizontal > row:not(:first-child) {
+  &.horizontal row.separator,
+  &.separators.horizontal > row {
     border-left: 1px solid $_treeview_borders_color;
   }
-  &:not(.horizontal) row.separator:not(:first-child),
-  &.separators:not(.horizontal) > row:not(:first-child) {
-    border-top: 1px solid $_treeview_borders_color;
+  &:not(.horizontal) row.separator,
+  &.separators:not(.horizontal) > row {
+    border-bottom: 1px solid $_treeview_borders_color;
   }
 }