Permission denied error while using CP Command

On Nautilus App Server 3 an issue was observed by security team. They found some malicious content within website code. After digging into the issue they found that there might be more infected files. Before doing a cleanup they would like to find out all similar files and copy them to a safe location for further investigation. Accomplish the task as per below mentioned requirements:

a. On App Server 3 at location /var/www/html/official find out all files (not directories) having .css extension.

b. Copy all those files along with their parent directory structure to location /official on same server.

c. Please make sure not to copy entire /var/www/html/official directory content.

*sudo find . -name .css

./official/wp-content/themes/twentynineteen/style-editor-customizer.css

./official/wp-content/themes/twentynineteen/style-rtl.css

./official/wp-content/themes/twentynineteen/style.css

[email protected] html]$ cp ./official/wp-admin/css/*.css /official

cp: cannot stat ‘./official/wp-admin/css/*.css’: Permission denied

For the above task god the List of files using find command

while using cp command getting permission denied error after using sudo also

Kind help me in resolving the issue