userChrome.css

#TabsToolbar > .titlebar-buttonbox-container{ visibility: collapse !important; }

.titlebar-buttonbox-container {
	display: none !important;
}

.titlebar-buttonbox-container > .titlebar-buttonbox{ height: 100%; }

#titlebar{
 -moz-box-ordinal-group: 2;
 -moz-appearance: none !important;
}

.titlebar-placeholder,
#TabsToolbar .titlebar-spacer{ display: none; }
/* Also hide the toolbox bottom border which isn't at bottom with this setup */
#navigator-toolbox::after{ display: none !important; }

@media (-moz-gtk-csd-close-button){ .titlebar-button{ -moz-box-orient: vertical } }

#nav-bar {
  height: 47px !important;
  padding: 0px 45px 0px 45px !important;

  background: linear-gradient(#e7e7e7, #d1d1d1) !important;
  border-top-left-radius: 4px !important;
  border-top-right-radius: 4px !important;
  border-top-width: 0px !important;
  border-bottom: 1px solid #979797 !important;
  box-shadow:
    inset 0 1px 0 0 rgba(255,255,255, 0.2),
    inset 0 -1px 0 0 rgba(255,255,255, 0.2) !important;
}

.tab-line {
  display: none !important;
}

#TabsToolbar{
  background: linear-gradient(#cbcbcb, #d5d5d5) !important;
  border-bottom: 1px solid #898989 !important;
  box-shadow: inset 0 1px 2px 1px rgba(0, 0, 0, 0.1) !important;
  max-height: 30px !important;
  min-height: 30px !important;
}

#tabbrowser-tabs {
  padding-inline-start: 0 !important;
  --tab-min-height: 29px !important;
  max-height: 29px !important;
  width: 100%;
}

.tabbrowser-tab {
  max-height: 29px !important;
  direction: rtl;
  margin-left: -1px !important;
}

.tabbrowser-tab:first-child {
  margin-left: 0 !important;
}

.tabbrowser-tab:not([visuallyselected="true"]) {
  border-left: 1px solid transparent !important;
}

.tabbrowser-tab::before,
.tabbrowser-tab::after {
  display: none !important;
}

.tab-background {
  border-top: 0 !important;
}

.tabbrowser-tab {
  border-top: 1px solid none !important;
  border-left: 1px solid #898989 !important;
  border-right: 1px solid #898989 !important;
  border-top-left-radius: 4px !important;
  border-top-right-radius: 4px !important;
  box-shadow: 0 0 1px 1px rgba(0, 0, 0, 0.1) !important;
}

.tab-background[selected="true"] {
  background-attachment: none !important;
  background: linear-gradient(to bottom, #d1d1d1, #c7c7c7) !important;
  border-top-left-radius: 4px !important;
  border-top-right-radius: 4px !important;
  box-shadow:
    inset 0 1px 0 0 rgba(255,255,255, 0.2),
    inset 0 -1px 0 0 rgba(255,255,255, 0.2),
    inset 1px 0 0 0 rgba(255,255,255, 0.2),
    inset -1px 0 0 0 rgba(255,255,255, 0.2) !important;
}

.tab-label {
  -moz-box-flex: 1 !important;
  color: #4b4b4b !important;
  text-align: center !important;
  text-shadow: 0 1px 0 rgba(255,255,255, 0.4) !important;
}

.tab-close-button {
  list-style-image: url(assets/close-tab.svg) !important;
}

#new-tab-button {
  list-style-image: url(assets/new-tab.svg) !important;
}

#back-button {
  list-style-image: url(assets/back.svg) !important;
  transform: scale(150%, 150%);
}

#forward-button {
  list-style-image: url(assets/forward.svg) !important;
  transform: scale(150%, 150%);
}

#reload-button {
  list-style-image: url(assets/reload.svg) !important;
  transform: scale(150%, 150%) !important;
}

#stop-button {
  list-style-image: url(assets/cancel.svg) !important;
  transform: scale(150%, 150%) !important;
}

#home-button {
  list-style-image: url(assets/home.svg) !important;
  transform: scale(150%, 150%) !important;
}

#urlbar,
#searchbar .searchbar-textbox {
  margin-top: 11px !important;
  margin-bottom: 11px !important;
  max-height: 25px !important;
  min-height: 25px !important;

  background: linear-gradient(to bottom, #eee, #fff) !important;
  background-clip: padding-box !important;
  border: 1px solid rgba(0,0,0, 0.25) !important;
  border-radius: 2.5px !important;
  box-shadow: 
              inset 0 0 0 1px rgba(0,0,0, 0.06),
              0 1px 0 0 rgba(255,255,255, 0.3) !important;
}

#tracking-protection-icon-container {
  display: none !important;
}

.toolbarbutton-1:not(#new-tab-button) {
  margin-bottom: 4px !important;
}

#os_style_close_trampover_gmail_com-browser-action {
  transform: translateX(-155px) !important;
  list-style-image: url(assets/close-tab.svg) !important;
}

#os_style_max_trampover_gmail_com-browser-action {
  list-style-image: url(assets/maximize.svg) !important;
  transform: translateX(155px) !important;
}