[libadwaita/wip/exalm/paned-cleanups] stylesheet: Clean up paned styles

[Alexander Mikhaylenko <alexm src gnome org>]

commit 8a188623e2e74044b6459f3c7afbd1a9c663b8d9
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Mon Nov 15 19:10:53 2021 +0500

    stylesheet: Clean up paned styles
    
    Make it recolorable, remove unused styles, remove gtk3 leftovers.

 src/stylesheet/widgets/_paned.scss | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)
---
diff --git a/src/stylesheet/widgets/_paned.scss b/src/stylesheet/widgets/_paned.scss
index 8aa30fb6..1c108bee 100644
--- a/src/stylesheet/widgets/_paned.scss
+++ b/src/stylesheet/widgets/_paned.scss
@@ -2,21 +2,13 @@ paned {
   > separator {
     min-width: 1px;
     min-height: 1px;
-    -gtk-icon-source: none; // defeats the ugly default handle decoration
-    border-style: none; // just to be sure
-    background-color: transparent;
-    // workaround, using background instead of a border since the border will get rendered twice (?)
-    background-image: image($border_color);
+    background-color: $border_color;
     background-size: 1px 1px;
 
-    &:selected { background-image: image($accent_bg_color); } // FIXME is this needed?
-
     &.wide {
       min-width: 5px;
       min-height: 5px;
-      background-color: $window_bg_color;
-      background-image: image($border_color), image($border_color);
-      background-size: 1px 1px, 1px 1px;
+      background: none;
     }
   }
 
@@ -37,8 +29,8 @@ paned {
     &.wide {
       margin: 0;
       padding: 0;
-      background-repeat: repeat-y, repeat-y;
-      background-position: left, right;
+      box-shadow: inset  1px 0 $border_color,
+                  inset -1px 0 $border_color;
     }
   }
 
@@ -51,8 +43,8 @@ paned {
     &.wide {
       margin: 0;
       padding: 0;
-      background-repeat: repeat-x, repeat-x;
-      background-position: bottom, top;
+      box-shadow: inset 0  1px $border_color,
+                  inset 0 -1px $border_color;
     }
   }
 }