patch 9.1.0078: GTK3: using wrong style for pre-edit area

Problem:  GTK3: using wrong style for pre-edit area
Solution: remove the widget name, adjust css
          (lilydjwg)

closes: #13972

Signed-off-by: lilydjwg <lilydjwg@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/gui_xim.c b/src/gui_xim.c
index c124e8b..345b3a4 100644
--- a/src/gui_xim.c
+++ b/src/gui_xim.c
@@ -325,7 +325,7 @@
 #if GTK_CHECK_VERSION(3,16,0)
     {
 	GtkStyleContext * const context
-				  = gtk_widget_get_style_context(gui.drawarea);
+				  = gtk_widget_get_style_context(preedit_label);
 	GtkCssProvider * const provider = gtk_css_provider_new();
 	gchar		   *css = NULL;
 	const char * const fontname
@@ -349,7 +349,7 @@
 	    fontsize_propval = g_strdup_printf("inherit");
 
 	css = g_strdup_printf(
-		"widget#vim-gui-preedit-area {\n"
+		"#vim-gui-preedit-area {\n"
 		"  font-family: %s,monospace;\n"
 		"  font-size: %s;\n"
 		"  color: #%.2lx%.2lx%.2lx;\n"