fenix-fox/chrome/Fx65_tabs_on_bottom.css

/* Modify to change window drag space width */
/*
Use Fx65_tabs_on_bottom_menubar_on_top_patch if you
have menubar permanently enabled and want it on top
 */

:root{
  --uc-titlebar-padding: 0px;
  --uc-window-control-width: 138px
}
:root[sizemode="maximized"][tabsintitlebar]{ --uc-titlebar-padding: 8px }
:root[tabsintitlebar="true"] #nav-bar{ --window-drag-space-width: 24px; }

.titlebar-buttonbox-container{
  position: fixed;
  top: var(--uc-titlebar-padding,0px);
  right:0;
  height: 40px;
}

:root[uidensity="compact"] .titlebar-buttonbox-container{ height: 32px }

#toolbar-menubar[inactive] > .titlebar-buttonbox-container{ opacity: 0 }

#navigator-toolbox{ padding-top: var(--uc-titlebar-padding,0px) !important; }


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

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

/* Space to drag the window on both sides of navbar */
:root[tabsintitlebar="true"]:not([inFullscreen]) #nav-bar{
  padding-right: calc(var(--uc-window-control-width) + var(--window-drag-space-width,0px));
  padding-left: var(--window-drag-space-width,0px)
}

.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; }