function plt_hide_responsive_add_ons_menus() {
//Hide the "Responsive" menu.
remove_menu_page('responsive_add_ons');
//Hide the "Appearance → Custom Fonts" menu.
remove_submenu_page('themes.php', 'edit-tags.php?taxonomy=responsive_custom_fonts');
}
add_action('admin_menu', 'plt_hide_responsive_add_ons_menus', 102);