[fractal/fractal-next] message-image: Improve fallback background color

[Julian Sparber <jsparber src gnome org>]

commit f2752b286345626eec14f345cc2ca28811b432e1
Author: Kévin Commaille <zecakeh tedomum fr>
Date:   Thu Dec 16 19:01:06 2021 +0100

    message-image: Improve fallback background color
    
    Works for both light and dark themes.

 data/resources/style.css | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/resources/style.css b/data/resources/style.css
index 5b172e45..bc460033 100644
--- a/data/resources/style.css
+++ b/data/resources/style.css
@@ -215,7 +215,7 @@ headerbar.flat {
 
 .room-history .event-content .thumbnail {
   border-radius: 6px;
-  background-color: @light_3;
+  background-color: @borders;
 }
 
 .room-history .event-content .thumbnail .osd.circular {