github.com-nboughton-dotfiles/gtk-3.0/gtk.css

decoration {
    box-shadow: none;
    border-radius: 0px;
}

decoration:backdrop {
    box-shadow: none;
}

.titlebar,
.titlebar .background,
.window-frame,
.window-frame:backdrop {
    border-radius: 0px;
    box-shadow: none;
}

/*
.window-frame, .window-frame:backdrop {
	box-shadow: none;
	border-style: none;
	margin: 0;
	border-radius: 0px;
}

.window-frame.csd.popup {
       box-shadow: none;
}

.header-bar {
	background-image: none;
	background-color: #061921;
	box-shadow: none;
}
*/