[gtk] Adwaita: error labels insensitive & backdrop states

[Matthias Clasen <matthiasc src gnome org>]

commit a498aca3ab364f4b3b13448fd94c30a4fa119420
Author: Jakub Steiner <jimmac gmail com>
Date:   Mon Aug 17 10:00:29 2020 +0200

    Adwaita: error labels insensitive & backdrop states
    
    - address colored labels for the two states
    
    See https://gitlab.gnome.org/GNOME/gtk/-/issues/3063#note_891618

 gtk/theme/Adwaita/_common.scss | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index a4783877f1..8ab52c8010 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -180,7 +180,7 @@ label {
 
   &.error {
    color: $error_color;
-   &:disabled { color: $insensitive_fg_color; }
+   &:disabled { color: transparentize($error_color,0.5); }
   }
 }