[gtk/popup-shadow-width] Adwaita: bring borders for tiled

[Matthias Clasen <matthiasc src gnome org>]

commit 7cc31d81f58b89106c50ff5f1a4c2a026a9413e3
Author: Jakub Steiner <jimmac gmail com>
Date:   Thu Feb 11 15:16:57 2021 +0100

    Adwaita: bring borders for tiled
    
    Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/3661

 gtk/theme/Adwaita/_common.scss | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 03bd00f154..bac45c3a3c 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -4103,12 +4103,18 @@ window {
   }
 
   &.maximized,
-  &.fullscreen,
+  &.fullscreen { border-radius: 0; box-shadow: none; }
+
   &.tiled,
   &.tiled-top,
   &.tiled-left,
   &.tiled-right,
-  &.tiled-bottom { border-radius: 0; box-shadow: none; }
+  &.tiled-bottom {
+   border-radius: 0;
+   box-shadow: 0 0 0 1px $_wm_border_backdrop;
+
+   &:backdrop { box-shadow: 0 0 0 1px $_wm_border_backdrop; }
+  }
 
   &.popup { box-shadow: none; }