remove bottom boder on title bars on gnome 3.16

gtk.css

/* ~/.config/gtk-3.0/gtk.css */
/* Get rid of unsightly line in ssd title bar and reduce button padding */

.ssd .titlebar {
    border: none;
    background-image: linear-gradient(to bottom,
                                      shade(@theme_bg_color, 1.042),
                                      shade(@theme_bg_color, 0.999));
    box-shadow: none;
    border-top: 1px solid shade(@theme_bg_color, 1.072);
}

.ssd .titlebar:backdrop {
    background-image: linear-gradient(to bottom, @theme_bg_color);
}

.ssd .titlebar .button.titlebutton {
    padding: 3px;
}

.menubar {
    background-image: linear-gradient(to bottom,
                                      shade(@theme_bg_color, 0.999),
                                      shade(@theme_bg_color, 0.985));
    border-bottom: 1px solid shade(@theme_bg_color, 0.679);
}

.menubar:backdrop {
    background-image: linear-gradient(to bottom, @theme_bg_color);
}