File with translation can be found here http://blog.sadtg.ru/lang_ru.inc.zip

Thank you for idea, the source of error really was in the css encoding.
Server automatically adds "charset=windows-1251" declaration and FF can't deal with it on UTF-8 page.
Resolution was to replace
header('Content-type: text/css');
in line 60 of serendipity.css.php file with
header('Content ...

Hi!

That's strange, your base webpage says it's using "UTF-8" charset, but when I request your CSS stylesheet, it uses win-1251 as the charset. I believe that Firefox might be confused by this. Do you know how this happens?

Which charset have oyu set in the serendipity configuration? UTF-8 or ...

Hi there!

I've just installed s9y on http://blog.sadtg.ru and there is a problem with appearance in Mozilla Firefox. Templates looks perfectly in IE and Opera, but in FF it looks like there is no template at all. I have no clue where the problem may be...