Hello Elvira,
Sorry for late reply to this,
I have checked in your site again, it seems like the browser still loading the old css code, because i have applied that css code, the browser doesn't load it, please have a check my attachment "Pic2", I'm suspected that was cached, you have to consult this with your current template provider and see how it goes.
Also consult this with your template provider => check my video link :
http://screencast.com/t/cbMuAQlKhw
I have do another testing, if i change your template to Joomla default template(Protostar), everything is work fine.