[gtk/wip/baedert/for-master: 17/19] Adwaita: Fix calendar header button backdrop bg color

[Timm Bäder <baedert src gnome org>]

commit 716b5afe6a40ef8c1f7d7e05c35e330bbe7e9d9e
Author: Timm Bäder <mail baedert org>
Date:   Wed Sep 23 05:58:40 2020 +0200

    Adwaita: Fix calendar header button backdrop bg color

 gtk/theme/Adwaita/_common.scss | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 2ab2e5e5f2..56e0a8d277 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -3255,6 +3255,9 @@ calendar {
       background: none;
       border-radius: 0;
     }
+    > button:backdrop {
+      background: none;
+    }
   }
 
   > grid {