[gtk/wip/jimmac/hc-switch-border] HC: switch border color

[Jakub Steiner <jimmac src gnome org>]

commit 3a5eee7dbe127d32b38764cd546a5c1d071af4da
Author: Jakub Steiner <jimmac gmail com>
Date:   Thu Jan 7 12:44:53 2021 +0100

    HC: switch border color
    
    - lighten inverted HC borders while darkening the regular/light variant
    
    Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/3460

 gtk/theme/HighContrast/_colors-hc.scss | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/theme/HighContrast/_colors-hc.scss b/gtk/theme/HighContrast/_colors-hc.scss
index b91e12ca38..f1535a64cf 100644
--- a/gtk/theme/HighContrast/_colors-hc.scss
+++ b/gtk/theme/HighContrast/_colors-hc.scss
@@ -22,3 +22,5 @@ $focus_border_color: if($variant == 'light', transparentize($selected_bg_color,
 $alt_focus_border_color: if($variant == 'light', white, transparentize(white,0.4));
 
 $dim_label_opacity: 0.9;
+
+$switch_borders_color: if($variant == 'light',darken($switch_bg_color,15%),lighten($switch_bg_color,15%));