About CSS Caching Test

Checks if your page is using caching headers for all CSS resources. Users browsers will check for these headers and, if any, will cache the CSS resources until the specified date (so that it does not keep re-fetching the unchanged file from your server). This speeds up your site the next time returning visitors arrive at your site and require the same CSS resource.

In order to reduce the number of HTTP requests, you can use the HTTP Expires header to set an expiration time for your CSS resources or any other content type. You can add the following lines into your .htaccess file:

        <IfModule mod_expires.c>
            ExpiresActive on
        
            ExpiresByType text/css "access plus 1 month"
        </IfModule>