Workaround for cut buttons in some gtk3 dialogs

Upstream bugreport: https://bugzilla.gnome.org/show_bug.cgi?id=710909

gtk-3.0/gtk-widgets.css

@@ -10,6 +10,8 @@
     -GtkButton-image-spacing: 0;
     -GtkButton-inner-border: 1;
     -GtkButton-interior-focus: true;
+    -GtkButtonBox-child-min-height: 24;
+    -GtkButtonBox-child-internal-pad-y: 1;
     -GtkCheckButton-indicator-size: 16;
     -GtkCheckMenuItem-indicator-size: 14;
     -GtkExpander-expander-size: 8;