<?php

$current = array(
	'tool_situs' => array(
		'template' => 'aa', 
		'title' => 'bb'
	),
	'style' => array(
		'title' => array(
			'color' => 'red',
			'font-size' => '20px'
		)
	)
);

$new = array(
	'tool_situs' => array(
		'title' => 'ddd'
	),
	'style' => array(
		'title' => array(
			'color' => 'blue',
		)
	)
);

header('Content-type: text/plain');

$result = array_replace_recursive($current, $new);


print_r($result);