hide title bar on maximized windows (works on gnome-shell 3.32)

gtk.css

/* 
CREDIT: Josh Sherman (https://joshtronic.com/2017/07/26/hide-title-bars-in-gnome-shell)
USAGE: copy and paste the code bellow in to ~/.config/gtk-3.0/gtk.css

*/

window.ssd.maximized separator:first-child + headerbar:backdrop,
window.ssd.maximized separator:first-child + headerbar,
window.ssd.maximized headerbar:first-child:backdrop,
window.ssd.maximized headerbar:first-child,
window.ssd.maximized headerbar:last-child:backdrop,
window.ssd.maximized headerbar:last-child,
window.ssd.maximized stack headerbar:first-child:backdrop,
window.ssd.maximized stack headerbar:first-child,
window.ssd.maximized stack headerbar:last-child:backdrop,
window.ssd.maximized stack headerbar:last-child,
window.ssd.maximized decoration, window.ssd.maximized headerbar.titlebar {
  border-radius: 0;
}

window.ssd.maximized headerbar * {
  margin-top: -100px;
  color: #1c2022; /* May need to tweak, this matches Adwaita Dark */
}

window.ssd.maximized headerbar.titlebar, window.ssd.maximized headerbar.titlebar button.titlebutton {
  border: none;
  font-size: 0;
  height: 0;
  margin: 0;
  max-height: 0;
  min-height: 0;
  padding: 0;
}