Hide a home tab for root site SharePoint 2013 Server

As in title:

I was wondering if you could help me with my issue as I am not a designer and seem to have some trouble with a simple requirement.
I need to hide a first home tab in a top nav menu for a site collection root page. It is there, next to a logo which also works as a home site link. I accomplished this in SP2010 adding simple CSS to the default CSS file:

<style type="text/css">
 .s4-tn li.static > a{ 
display: none !important; 
} 
.s4-tn li.static > ul a{ 
display: block !important; 
}
 </style>

In SP2013 Server, in site collection with publishing features activated- it does not work. I edit corev15.css but nothing happens! What should I do? Regards Lukas