[libadwaita/wip/exalm/backdrop: 18/27] stylesheet: Remove separate header bar border color for backdrop

[Alexander Mikhaylenko <alexm src gnome org>]

commit e9457af3a5ced2dc968ed05032dff285290ffc47
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Fri Apr 30 01:33:55 2021 +0500

    stylesheet: Remove separate header bar border color for backdrop
    
    It's not very noticeable in regular variants anymore, but was breaking high
    contrast.
    
    This was also the last separate backdrop color.
    
    Fixes https://gitlab.gnome.org/GNOME/libadwaita/-/issues/119

 src/stylesheet/_colors-public.scss      | 2 +-
 src/stylesheet/_colors.scss             | 3 ---
 src/stylesheet/widgets/_header-bar.scss | 1 -
 3 files changed, 1 insertion(+), 5 deletions(-)
---
diff --git a/src/stylesheet/_colors-public.scss b/src/stylesheet/_colors-public.scss
index ad1e9b5..6c3f257 100644
--- a/src/stylesheet/_colors-public.scss
+++ b/src/stylesheet/_colors-public.scss
@@ -75,7 +75,7 @@ widgets main borders color */
 
 /*
 widgets main borders color on backdrop windows */
-@define-color unfocused_borders #{"" +$backdrop_borders_color};
+@define-color unfocused_borders #{"" +$borders_color};
 
 /*
 these are pretty self explicative */
diff --git a/src/stylesheet/_colors.scss b/src/stylesheet/_colors.scss
index f3e102f..19a97e6 100644
--- a/src/stylesheet/_colors.scss
+++ b/src/stylesheet/_colors.scss
@@ -49,9 +49,6 @@ $insensitive_fg_color: mix($fg_color, $bg_color, 50%);
 $insensitive_bg_color: mix($bg_color, $base_color, 60%);
 $insensitive_borders_color: mix($borders_color, $bg_color, 80%);
 
-//colors for the backdrop state, derived from the main colors.
-$backdrop_borders_color: mix($borders_color, $bg_color, 80%);
-
 //special cased widget colors
 $suggested_bg_color: $selected_bg_color;
 $suggested_border_color: $selected_borders_color;
diff --git a/src/stylesheet/widgets/_header-bar.scss b/src/stylesheet/widgets/_header-bar.scss
index 1206fb8..232c011 100644
--- a/src/stylesheet/widgets/_header-bar.scss
+++ b/src/stylesheet/widgets/_header-bar.scss
@@ -17,7 +17,6 @@ headerbar {
   @include headerbar_fill(darken($bg_color, 10%));
 
   &:backdrop {
-    border-color: $backdrop_borders_color;
     background-color: $bg_color;
     background-image: none;