[gtk/wip/exalm/popover] Adwaita: use transparent borders for popovers

[Alexander Mikhaylenko <alexm src gnome org>]

commit 379669b153595fd1a33b200f6b08e7d5ba0407f4
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Mon Dec 2 21:54:37 2019 +0500

    Adwaita: use transparent borders for popovers
    
    Do the same thing as menus and windows do already.

 gtk/theme/Adwaita/_common.scss           | 7 +++++++
 gtk/theme/Adwaita/gtk-contained-dark.css | 2 ++
 gtk/theme/Adwaita/gtk-contained.css      | 2 ++
 3 files changed, 11 insertions(+)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 27cc656bb7..dbeb5c31ed 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -2282,6 +2282,13 @@ popover.background {
     border-radius: $popover_radius;
   }
 
+  .csd & {
+    $_popover_border: if($variant=='light', transparentize(black, 0.77), transparentize($borders_color, 
0.1));
+
+    background-clip: padding-box;
+    border-color: $_popover_border;
+  }
+
   box-shadow: 0 1px 2px transparentize(black, 0.7);
 
   &:backdrop {
diff --git a/gtk/theme/Adwaita/gtk-contained-dark.css b/gtk/theme/Adwaita/gtk-contained-dark.css
index 2d5f375da2..1a18c84305 100644
--- a/gtk/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/theme/Adwaita/gtk-contained-dark.css
@@ -795,6 +795,8 @@ popover.background { padding: 2px; background-color: #353535; box-shadow: 0 1px
 
 .csd popover.background, popover.background { border: 1px solid #1b1b1b; border-radius: 9px; }
 
+.csd popover.background { background-clip: padding-box; border-color: rgba(27, 27, 27, 0.9); }
+
 popover.background:backdrop { background-color: #353535; box-shadow: none; }
 
 popover.background > list, popover.background > .view, popover.background > iconview, popover.background > 
toolbar { border-style: none; background-color: transparent; }
diff --git a/gtk/theme/Adwaita/gtk-contained.css b/gtk/theme/Adwaita/gtk-contained.css
index 69d0992884..91ddb93660 100644
--- a/gtk/theme/Adwaita/gtk-contained.css
+++ b/gtk/theme/Adwaita/gtk-contained.css
@@ -803,6 +803,8 @@ popover.background { padding: 2px; background-color: #f6f5f4; box-shadow: 0 1px
 
 .csd popover.background, popover.background { border: 1px solid #cdc7c2; border-radius: 9px; }
 
+.csd popover.background { background-clip: padding-box; border-color: rgba(0, 0, 0, 0.23); }
+
 popover.background:backdrop { background-color: #f6f5f4; box-shadow: none; }
 
 popover.background > list, popover.background > .view, popover.background > iconview, popover.background > 
toolbar { border-style: none; background-color: transparent; }