userChrome.css

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#autohide-context {
  display:none!important;
}
#titlebar, #back-button, #forward-button, #nav-bar-overflow-button, .titlebar-placeholder  {
  display:none !important;
}
#urlbar, #PanelUI-button, #urlbar:hover {
  border: none !important;
  box-shadow: none !important;
  background: none !important;
}
#PanelUI-menu-button, .urlbar-history-dropmarker, .tab-close-button {
  opacity:0;
}
#urlbar {
  font-size:1.15em;
  filter: grayscale(100%);
}
.tab-content {
  filter: grayscale(100%);
}
#urlbar[pageproxystate="valid"] > #identity-box.verifiedIdentity > #identity-icon-label {
  color: #B1CBBA !important;
}
#pageActionButton {
  display: none !important;
}
#urlbar, #navigatortoolbox, .tabbrowser-tab {
  font-family: SF Mono, deja-vu-sans, Deja Vu Sans !important;
  letter-spacing: 0px;
  font-size: 0.7em;
}
#TabsToolbar .tabbrowser-tab .tab-line {
    display: none !important;
}
#TabsToolbar, #titlebar {
    -moz-appearance: -moz-mac-vibrancy-dark !important;
}