Thx for the help, i've found how to change this color...
For guys who search this too, here my code:
btw for the advertisement it lukly desappear but i don't know how... Well i've my result ^^
border: 1px solid #ce891c;
background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 #888888, stop: 1 #dddddd);
background-position: bottom right;
But now i need few other informations:
1: How it's called the frame over the comboframe where appear the header of the server ?
2: How change the resizing frame ? I want to change them colors; how to do this ?
3: How to set diferent colors between room channel and user like on this skin: http://img1.bildupload.com/708666f00...944107ee23.jpg ? I don't find the code in the .qss :/
Hope this time i'm going to be helped :P