"style" in struct GtkWidget

[Mariusz Bozewicz <plachninka wp pl>]

Hello
  I'm beginning with Gtk. I want to change color (background color) of
drawing area. For example:
GtkWidget *drawarea;
drawarea=gtk_drawing_area_new();
// I want to change color
drawarea->style->bg[]  // and here, why bg is array of 5 GdkColor elements 
                //  what does each element mean?
                Mariusz Bozewicz