Thread:Project:Support desk/Some css code does not work in common.css! Why/reply

I do not know off hand, but it is no magic. :-)

The page for which you say it works has a body tag with the according class ("page-Заглавная_страница") assigned to it.

Check the page, on which it does not work to see, how the class is called there. It might be called differently from what you think. Maybe the colon is causing the problem; if I remember correctly, colons are not allowed in CSS class names.