gtka

// Include gtk
#include <gtk/gtk.h>

static void on_activate (GtkApplication *app)
{
  GtkWidget *window = gtk_application_window_new (app);

  gtk_window_set_position (GTK_WINDOW(window),GTK_WIN_POS_CENTER);
  gtk_window_set_default_size(GTK_WINDOW(window), 400,50);
  gtk_container_set_border_width(GTK_CONTAINER(window),100);
 
  GtkWidget *boxwindows = gtk_box_new(GTK_ORIENTATION_VERTICAL, 10);
  GtkWidget *list = gtk_list_box_new ();
  GtkWidget *label1 = gtk_label_new("Nivel 1");
  GtkWidget *label2 = gtk_label_new("Nivel 2");
  GtkWidget *label3 = gtk_label_new("Nivel 3");

  //gtk_widget_set_sensitive(list, FALSE);

  gtk_list_box_insert (GTK_LIST_BOX(list),label1, 1);
  gtk_list_box_insert (GTK_LIST_BOX(list),label2, 2);
  gtk_list_box_insert (GTK_LIST_BOX(list),label3, 3);

  GtkWidget *btn2 =  gtk_button_new_with_label ("Siguiente");
  GtkWidget *boxbtn = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 10);

  gtk_box_pack_start(GTK_BOX(boxwindows), list, FALSE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(boxwindows), boxbtn, FALSE, TRUE, 0);

  gtk_box_pack_start(GTK_BOX(boxbtn), btn2, TRUE, TRUE, 0);

  gtk_container_add(GTK_CONTAINER(window), boxwindows);



  GtkCssProvider *cssProvider = gtk_css_provider_new();
  gtk_css_provider_load_from_path(cssProvider, "estilo.css", NULL);
  gtk_style_context_add_provider_for_screen(gdk_screen_get_default(), GTK_STYLE_PROVIDER(cssProvider), GTK_STYLE_PROVIDER_PRIORITY_USER);


  g_signal_connect_swapped (G_OBJECT(window), "destroy", G_CALLBACK (gtk_window_close), window);
  gtk_widget_show_all (window);

}

int main (int argc, char *argv[]) 
{

  GtkApplication *app = gtk_application_new ("By.Cristo.Arcris",
                                             G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (on_activate), NULL);
  return g_application_run (G_APPLICATION (app), argc, argv);
}