[gtksourceview] css: set some CSS defaults for the overview map

[Christian Hergert <chergert src gnome org>]

commit a204807298e5ce6b6caf9c6f228f40e8f50fe531
Author: Christian Hergert <chergert redhat com>
Date:   Thu Oct 14 17:56:19 2021 -0700

    css: set some CSS defaults for the overview map

 gtksourceview/GtkSourceView.css | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/gtksourceview/GtkSourceView.css b/gtksourceview/GtkSourceView.css
index d8974edf..2ad2fbd9 100644
--- a/gtksourceview/GtkSourceView.css
+++ b/gtksourceview/GtkSourceView.css
@@ -164,3 +164,8 @@ GtkSourceStyleSchemePreview.selected image {
   padding: 2px;
   margin: 6px;
 }
+
+textview.GtkSourceMap {
+  font-size: 1.75pt;
+  line-height: 4px;
+}