Delete the entire “cache” folder that is in the “static-server” directory. That will force its regeneration at the next page load. You might also need to clear the cache of your web browser.
If your site is already online and public, instead of clearing the cache, upgrade the version number of the file in both the filename and the HTML document where the CSS or JS file is included. Both the “static-server” and the web browser will consider it as a new file and therefore will load it right away without the need to clear any cache — This “new” file will be cached like other files, both by the web browser and by the “static-server” script.
index-nophp.html version which doesn’t have any specific caching.