## Questions about GtkWidget

1. How do I change the color of a widget?

   The background color of a widget is determined by the CSS style that applies to it. To change that, you can set style classes on the widget, and provide custom CSS to change the appearance. Such CSS can be loaded with `gtk_css_provider_load_from_file()` and its variants. See `gtk_style_context_add_provider()`.

2. How do I change the font of a widget?

   If you want to make the text of a label larger, you can use `gtk_label_set_markup()`:

       gtk_label_set_markup (label, "<big>big tex</big>");

   This is preferred for many apps because it’s a relative size to the user’s chosen font size. See `g_markup_escape_text()` if you are constructing such strings on the fly.

   You can also change the font of a widget by putting

       .my-widget-class {
         font: Sans 30;
       }

   in a CSS file, loading it with `gtk_css_provider_load_from_file()`, and adding the provider with `gtk_style_context_add_provider_for_display()`. To associate this style information with your widget, set a style class on its GtkStyleContext using `gtk_style_context_add_class()`. The advantage of this approach is that users can then override the font you have chosen. See the GtkStyleContext documentation for more discussion.

3. How do I disable/ghost/desensitize a widget?

   In GTK a disabled widget is termed insensitive. See `gtk_widget_set_sensitive()`.