How to modify the background color of a GtkTextView?

[mili <milimeter 163 com>]

Hi, anyone

  I wrote the following codes:
>>>>>>
TextRcStyle:=gtk_rc_style_new();
TextRcStyle^.base[0].red   :=54783;
TextRcStyle^.base[0].green :=55039;
TextRcStyle^.base[0].blue  :=54783;
pango_font_description_free(TextRcStyle^.font_desc);
font_desc:=pango_font_description_from_string('Simsun 16');
<<<<<<

Then I try to apply TextRcStyle to a text_view:

gtk_widget_modify_style(PGtkWidget(tree_view),MypanelSettings.TreeRcStyle);

The result is that font is modified correctly, but color remains white. Then I 
add the following line:

gtk_widget_modify_base(PGtkWidget(tree_view),GTK_STATE_NORMAL,@(MypanelSettings.TextRcStyle^.base[0]));

Now the color is also modified as what I want. So I think perhaps I used a 
wrong way of colors of GtkRcStyle. Can anybody give me an instruction on how 
to use correctly the GtkRcStyle and Color system?

Thank you very much.
Yours,
mili