function lxtx_wp_maintenance_mode(){
    if(!current_user_can('edit_themes') || !is_user_logged_in()){
    	$logo = 'https://www.您的域名.com'; // 请将此图片地址换为自己站点的 logo 图片地址
    	$blogname =  get_bloginfo('name');
    	$blogdescription = get_bloginfo('description');
        wp_die('<div style="text-align:center"><img src="'.$logo.'" alt="'.$blogname.'" /><br /><br />'.$blogname.'正在例行维护中，请稍候...</div>', '站点维护中 - '.$blogname.' - '.$blogdescription ,array('response' => '503'));
    }
}
add_action('get_header', 'lxtx_wp_maintenance_mode');