[gnome-sudoku] Update CSS for GTK+ 3.19

[Sahil Sareen <ssareen src gnome org>]

commit d88fd3845c9ab44c29dd2916a65c0fba9239da1a
Author: Sahil Sareen <sahil sareen hotmail com>
Date:   Sat Feb 27 22:52:49 2016 +0530

    Update CSS for GTK+ 3.19

 data/gnome-sudoku.css |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/data/gnome-sudoku.css b/data/gnome-sudoku.css
index 024c57d..e08c1a1 100644
--- a/data/gnome-sudoku.css
+++ b/data/gnome-sudoku.css
@@ -1,2 +1,2 @@
 /* Pixel-perfect compatibility with games that have a Button without ButtonBox. */
-GtkButtonBox { -GtkButtonBox-child-internal-pad-x:0; }
+buttonbox { -GtkButtonBox-child-internal-pad-x:0; }