userChrome.css

:root {
  --urlbar-primary-colour: #434c5e;
  --urlbar-invert-colour: #2e3440;
}

.browser-toolbar:not(.titlebar-color) {
  background: var(--urlbar-invert-colour) !important;
}

#TabsToolbar {
  background-color: var(--urlbar-invert-colour) !important;
  margin-bottom: 0px !important;
  margin-top: 0px !important;
  margin-left: 35vw !important;
  max-height: 35px !important;
  height: 30px !important;
}
#nav-bar {
  margin-top: -30px !important;
  margin-left: 0px !important;
  margin-right: 65vw !important;
  height: 30px;
  background-color: var(--urlbar-invert-colour) !important;
}

#PersonalToolbar {
  --uc-bm-height: 23px;
  --uc-bm-padding: 3px;
}
:root[uidensity="compact"] #PersonalToolbar {
  --uc-bm-padding: 1px;
}
:root[uidensity="touch"] #PersonalToolbar {
  --uc-bm-padding: 6px;
}
#PersonalToolbar:not([customizing]) {
  margin-bottom: calc(2px - var(--uc-bm-height) - 2 * var(--uc-bm-padding));
  transform: rotateX(90deg);
  transform-origin: top;
  transition: transform 135ms linear 48ms !important;
  z-index: 1;
}
#PlacesToolbarItems > .bookmark-item {
  padding-block: var(--uc-bm-padding) !important;
}
#nav-bar:focus-within + #PersonalToolbar,
#navigator-toolbox:hover > #PersonalToolbar {
  transform: rotateX(0);
}

#PanelUI-button,
.panel-arrow {
  -moz-box-ordinal-group: 0 !important;
}
#navigator-toolbox {
  border-bottom: 0px solid var(--chrome-content-separator-color) !important;
}
#urlbar-container,
#search-container {
  padding-block: 0px !important;
  margin-inline: 0px !important;
}
.tab-background[selected="true"] {
  background-color: var(--urlbar-primary-colour) !important;
  background-image: none !important;
}
.tab-background:not([selected]) {
  background-color: var(--urlbar-invert-colour) !important;
}
.tab-line {
  height: 0px !important;
}
#navigator-toolbox {
  --tabs-border-color: var(--urlbar-invert-colour) !important;
}

#urlbar,
#urlbar[focused="true"],
.searchbar-textbox,
#urlbar:hover,
.searchbar-textbox:hover {
  background: var(--urlbar-primary-colour) !important;
  color: white !important;
  padding: 0 0px !important;
  border-radius: 0 !important;
  outline: none !important;
  box-shadow: 0 0 0 !important;
  border: 0 solid transparent !important;
  height: 30px !important;
  -moz-appearance: none;
  margin: 0px 0px !important;
  cursor: default;
}

#star-button-box,
#reader-mode-button,
#pageActionSeparator,
#pocket-button-box,
.autocomplete-history-dropmarker,
.urlbar-history-dropmarker.urlbar-icon.chromeclass-toolbar-additional,
#TabsToolbar .titlebar-placeholder[type="pre-tabs"],
#identity-icon-labels {
  display: none !important;
}