[gtksourceview/wip/chergert/vim] css: use theme_base_color for content area

[Christian Hergert <chergert src gnome org>]

commit e82c81365ab4cee8efa86196f904b7ef8c281675
Author: Christian Hergert <chergert redhat com>
Date:   Tue Oct 26 12:16:35 2021 -0700

    css: use theme_base_color for content area
    
    This is more likely to work with things like libadwaita.

 gtksourceview/GtkSourceView.css | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtksourceview/GtkSourceView.css b/gtksourceview/GtkSourceView.css
index 2ad2fbd9..67156b1d 100644
--- a/gtksourceview/GtkSourceView.css
+++ b/gtksourceview/GtkSourceView.css
@@ -12,7 +12,7 @@ GtkSourceAssistant {
 }
 
 GtkSourceAssistant.completion {
-  background-color: @content_view_bg;
+  background-color: @theme_base_color;
   border: none;
   min-width: 150px;
 }