Smaller tabs in Gnome terminal. Makes the tabs take less space vertically.

gtk.css

# Put this file in ~/.config/gtk.css

TerminalWindow .notebook {
   padding: 0;
}

TerminalWindow .notebook tab:active {
   border: 1px solid #999;
}

TerminalWindow .notebook tab {
}

TerminalWindow .notebook .button {
   padding: 2 2 2 10;
   border: 0;
}
TerminalWindow .notebook .button:active {
   padding: 2 2 2 10;
   background-image: none;
   border: 0;
}