How change the white background/text background of window/text bar

view full story

http://askubuntu.com – Sorry if my question bothers you, but I really searched everywhere and tried everything. I would like to change the white background of my window, which is appearing too in the address bar (like browser). I was tryng to change the theme CSS of GTK2 and GTK3.0 and another scripts of the theme, and tried another themes. I would like to change the eye-killing white to grey. In Windows you could just change that easily with the theme changer. In Xubuntu (i'm using XFCE), this seems unpossible. I switched back to Ubuntu, but there I couldn't change this, even theyre using same principles. I add (HowTos)