[gtk+] Adwaita: Fix treeview separators in backdrop

[Matthias Clasen <matthiasc src gnome org>]

commit 366527c2d0ec76bfc6cd0f8255cb4c8b36303882
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Jan 10 13:04:10 2015 -0500

    Adwaita: Fix treeview separators in backdrop
    
    https://bugzilla.gnome.org/show_bug.cgi?id=742702

 gtk/theme/Adwaita/_common.scss |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 305c593..cf1a559 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -1349,6 +1349,10 @@ GtkTreeView.view {
     &:backdrop { color: $backdrop_insensitive_color; }
   }
 
+  &.separator:backdrop {
+    color: transparentize(black, 0.9);
+  }
+
   &:backdrop {
     border-left-color: mix($backdrop_fg_color, $backdrop_bg_color, 50%);
     border-top: $backdrop_bg_color;