customize tab on ubuntu terminal

display.md

gtk.css

/*
   create new file if doesn't exists
   ~/.config/gtk-3.0/gtk.css
*/

TerminalWindow .notebook {
    border: 0;
    padding: 0;
    color: #4E6777;
    font-size: 10px;
    background-color: shade(#313131, 1);
}

TerminalWindow .notebook tab:active {
    background-color: shade(#313131,1);
}

TerminalWindow .notebook tab {
    border-radius: 0px;
    padding: 3px;
    background-color: shade(#222, 1);
}