While most of what you've written is fairly close to accurate, you'd make a better case if you omitted weasel-words like "probably," "somewhere," and "obviously" and if your explanation of the interactions among server, site and browser were clearer... and supported by the readily available specifics:

The source to which you refer OP is:

<!-- Theme 1092: Web safe blue PerlMonks Theme    -->
    <link rel="stylesheet" href="/css/common.css" type="text/css" />
    <link rel="stylesheet" href="?node_id=204962" type="text/css" />
[download]

The first can be seen at http://www.perlmonks.com/css/common.css (NB: if perlmonks.com is not your server, substitute perlmonks.org). The second is available at http://www.perlmonks.com/index.pl?node_id=204962.

But consider: how is all of this verbose reply¹ really more helpful (at any immediate level) to OP than a simple statement of fact:

Browsers get css from the server by reading a particular URL supplied in the .html.

And that's only a marginally useful expansion of moritz' original reply.

¹ Yep, this is excessively wordy, too!