Browsers does not reflects updates in the code

While working on HTML, CSS (and more) like changing the code and refreshing the browser, after updating the files (local or remote [ftp]) and refreshing the browser won't reflect the changes. Many browses suffer from this problem. Firefox, Safari and even Opera (Opera GX); any updates or changes to the remote or local files won't be reflected. This problem is not new, it's been around for decades! Even if I upload the new file to the server and refresh in FF it is not showing the new code styles, I have emptied cookies. I am confused; any ideas?