Why are modified WordPress theme styles not showing up when migrating to another local web server?

Question

css

Hello.
OpenServer (apache 2.2, php 5.3, mysql 5.5) is installed on the local machine, WordPress 4.5.2 is installed on it with the Twenty Fifteen theme.
I changed the backgrounds through the theme's admin panel, and then manually changed the theme's styles by editing css. On my local machine, the changed styles are displayed, although the first time the site loads, the default styles from the theme are first visible for a second.
When moving the site to another local machine with the same OpenServer, the theme styles I changed are not displayed at all.
What to do? How do I explicitly tell WordPress to only use my edited styles, without the original theme styles?

Answer 1

Openserver is portable in fact. Just copy the entire openserver folder to another local computer and run from there.

Answer 2

You most likely need an htaccess file, caching of css files needs to be removed there. If there is a plugin for caching, then update through it.
I didn't really understand about the admin panel... Did you import the database? if not, then do it.