Creates a standalone GtkStyleContext, this style context
won't be attached to any widget, so you may want
to call gtk_style_context_set_path() yourself.
Note
This function is only useful when using the theming layer
separated from GTK+, if you are using GtkStyleContext to
theme GtkWidgets, use gtk_widget_get_style_context()
in order to get a style context ready to theme the widget.
Creates a standalone GtkStyleContext, this style context won't be attached to any widget, so you may want to call gtk_style_context_set_path() yourself. Note This function is only useful when using the theming layer separated from GTK+, if you are using GtkStyleContext to theme GtkWidgets, use gtk_widget_get_style_context() in order to get a style context ready to theme the widget.