/* カーソルでなぞった文字反転 */
function custom_admin_selection_style() {
    echo '<style>
        ::selection {
            background: #3399ff !important;
            color: white !important;
        }
    </style>';
}
add_action('admin_head', 'custom_admin_selection_style');<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /usr/home/hbv10033b5hj/html/blog/wp-content/themes/fcblog/functions.php:42) in <b>/usr/home/hbv10033b5hj/html/blog/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1775</b><br />
<?xml version="1.0"?>
<oembed><code>rest_missing_callback_param</code><message>&#x30D1;&#x30E9;&#x30E1;&#x30FC;&#x30BF;&#x4E0D;&#x8DB3;: url</message><data><status>400</status><params><oembed>url</oembed></params></data></oembed>