#### 2. `functions.php`（中枢処理）
```php
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://ramsec.jp/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://ramsec.jp/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://ramsec.jp/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://ramsec.jp/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://ramsec.jp/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>