Gtk3 CSS for MenuItems

gistfile1.c

/* COMPILE WITH: gcc -Wall -o icon3 `pkg-config --cflags --libs gtk+-3.0` a.c */

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

static void cb_left_click(GtkStatusIcon * icon, gpointer data)
{
	static GtkWidget *window = NULL;

	if (window == NULL) {
		window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
		gtk_window_set_title(GTK_WINDOW(window), "Status Icon");

		g_signal_connect(window, "delete-event",
				 G_CALLBACK(gtk_main_quit), NULL);
		gtk_widget_show(window);
	}
}

static void cb_right_click(GtkStatusIcon * icon, int button, int time,
			   gpointer data)
{
	GtkWidget *menu;

	menu = gtk_menu_new();
	gtk_widget_set_name(GTK_WIDGET(menu), "mymenu");
	GtkWidget *item1 = gtk_menu_item_new_with_label("First");

	GtkWidget *item2 = gtk_menu_item_new_with_label("Second");

	gtk_menu_shell_append(GTK_MENU_SHELL(menu), item1);
	gtk_menu_shell_append(GTK_MENU_SHELL(menu), item2);

	gtk_widget_show_all(menu);
	gtk_menu_popup(GTK_MENU(menu),
		       NULL,
		       NULL, gtk_status_icon_position_menu, icon, button, time);
}

int main(int argc, char *argv[])
{
	GtkStatusIcon *icon;
	GtkCssProvider *provider;
	GdkDisplay *display;
	GdkScreen *screen;

	gtk_init(&argc, &argv);

	icon = gtk_status_icon_new_from_stock(GTK_STOCK_MEDIA_PLAY);

	g_signal_connect(G_OBJECT(icon), "activate", G_CALLBACK(cb_left_click),
			 NULL);
	g_signal_connect(G_OBJECT(icon), "popup-menu",
			 G_CALLBACK(cb_right_click), NULL);

	provider = gtk_css_provider_new();
	display = gdk_display_get_default();
	screen = gdk_display_get_default_screen(display);
	gtk_style_context_add_provider_for_screen(screen,
						  GTK_STYLE_PROVIDER(provider),
						  GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);

	gsize bytes_written, bytes_read;

	const gchar *home = "g.css";

	GError *error = 0;

	gtk_css_provider_load_from_path(provider,
					g_filename_to_utf8(home, strlen(home),
							   &bytes_read,
							   &bytes_written,
							   &error), NULL);
	g_object_unref(provider);

	gtk_main();
	return 0;
}

/*
#mymenu {
    background-color: red;
    color: green;
    font-weight:bold;
}

#mymenu :hover {
    background-color: red;
    color: blue;
    font-weight:bold;
}

*/