Firefox

/* Firefox Quantum userChrome.css tweaks ************************************************/
/* Github: https://github.com/aris-t2/customcssforfx ************************************/
/****************************************************************************************/




#main-window { background-color: transparent !important; -moz-appearance: -moz-win-glass !important; }

/* TABS: on bottom */
#navigator-toolbox toolbar:not(#nav-bar):not(#toolbar-menubar) {-moz-box-ordinal-group:10}
#TabsToolbar {-moz-box-ordinal-group:1000!important}

#TabsToolbar {
 position: absolute !important;
 bottom: 0 !important;
 width: 100vw !important;
}

#tabbrowser-tabs {
  width: 100vw !important;
}
#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {padding-bottom: var(--tab-min-height) !important;}

/* TABS: height */
:root {
 --tab-toolbar-navbar-overlap: 0px !important;
 --tab-min-height: 33px !important; /* adjust to suit your needs */
}
:root #tabbrowser-tabs {
 --tab-min-height: 33px !important; /* needs to be the same as above under :root */
 --tab-min-width: 80px !important;
}


#tabbrowser-tabs,
#tabbrowser-tabs > .tabbrowser-arrowscrollbox,
.tabbrowser-tabs[positionpinnedtabs] > .tabbrowser-tab[pinned] {
  min-height: var(--tab-min-height) !important;
  max-height: var(--tab-min-height) !important;
}

/* drag space */
.titlebar-spacer[type="pre-tabs"],
.titlebar-spacer[type="post-tabs"] {
  width: 40px;
}

/* Override vertical shifts when moving a tab */
#navigator-toolbox[movingtab] > #titlebar > #TabsToolbar {
  padding-bottom: unset !important;
}
#navigator-toolbox[movingtab] #tabbrowser-tabs {
  padding-bottom: unset !important;
  margin-bottom: unset !important;
}
#navigator-toolbox[movingtab] > #nav-bar {
  margin-top: unset !important;
}

/* hide windows-controls */
#TabsToolbar #window-controls {display: block !important;}

/* move caption buttons to right of Tab bar */
#main-window[tabsintitlebar]:not([inFullscreen="true"]) #toolbar-menubar[autohide="true"] ~ #TabsToolbar .titlebar-buttonbox-container {
 position: fixed !important;
 right: 0 !important;
 top: calc(6px + var(--tab-min-height)) !important;
 display: block !important;
 visibility: visible !important;
}
#toolbar-menubar[autohide="true"] ~ #TabsToolbar {padding-right: 100px !important;}


#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab {
  color: white !important;
  text-shadow: 1px 1px 1px black !important;
}

#TabsToolbar:not(:-moz-lwtheme) .tabs-newtab-button {
  fill: white !important;
  color: white !important;
}

/* remove default tab colors */
#TabsToolbar .tabbrowser-tab[visuallyselected="true"],
#TabsToolbar .tabbrowser-tab,
#TabsToolbar .tabbrowser-tab .tab-background {
  background: unset !important;
  border: unset !important;
}

/* tab border color */
#TabsToolbar .tabbrowser-tab:not(:-moz-lwtheme):not([selected]) .tab-content,
#TabsToolbar:not(:-moz-lwtheme) .tabs-newtab-button,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab .tab-content {
  border-top: 1px solid rgba(255,255,255,.0) !important;
  border-left: 1px solid rgba(255,255,255,.0) !important;
  border-right: 1px solid rgba(255,255,255,.0) !important;
}

/* transparent tabs */
#TabsToolbar:not(:-moz-lwtheme) .tabs-newtab-button,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab .tab-content {
  background-image: linear-gradient(to top,rgba(255,255,255,.0),rgba(255,255,255,.2)) !important;
}
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab .tab-content[selected="true"] {
  background-image: linear-gradient(to top,rgba(255,255,255,.0),rgba(255,255,255,.7)) !important;
}
#TabsToolbar:not(:-moz-lwtheme) .tabs-newtab-button:hover,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab:hover .tab-content:not([selected="true"]) {
  background-image: linear-gradient(to top,rgba(255,255,255,.1),rgba(255,255,255,.3)) !important;
}

#main-window #titlebar-buttonbox .titlebar-button {

                list-style-image: none !important;
                padding: 9px 17px 9px 16px !important;
                transition: background-color linear 100ms !important;
        }

#browser-bottombox, #status-bar, #status-bar > *, #nav-bar, #PersonalToolbar, #addon-bar, #main-window[tabsontop="false"] ,
    #main-window[tabsontop="false"] #PersonalToolbar[collapsed="false"] + #TabsToolbar,
    #main-window[tabsontop="false"] [id^="__customToolbar"]:not([collapsed="true"]) ~ #TabsToolbar
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: #FFFFFF !important;
  -moz-appearance: none !important;
}

#urlbar
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: #FFFFFF !important;
  font-weight: normal!important;
  text-shadow: grey 1px 1px 5px !important;
  border: none !important;
  border-radius: 2px 0 0 0 !important;
  margin: 0 !important;
  box-shadow: inset 0px 0px 3em 0px rgba(255,255,255,.5) !important;
}
 #navigator-toolbox .searchbar-textbox
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: none!important;
  font-weight: normal!important;
  text-shadow: grey 1px 1px 5px !important;
  border: none !important;
  border-radius: 2px 0 0 0 !important;
  margin: 0 !important;
}
#urlbar:hover
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: #FFFFFF !important;
  text-shadow: #000000 1px 1px 5px !important;
  box-shadow: inset 0px 0px 5em 0px rgba(255,255,255,.5) !important;
}


#searchbar
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: #FFFFFF !important;
  font-weight: normal!important;
  text-shadow: grey 1px 1px 5px !important;
  border: none !important;
  border-radius: 2px 0 0 0 !important;
  margin: 0 !important;
  box-shadow: inset 0px 0px 3em 0px rgba(255,255,255,.5) !important;
}
#searchbar:hover
{
  background: transparent !important; -moz-appearance: -moz-win-glass !important;
  color: #FFFFFF !important;
  text-shadow: #000000 1px 1px 5px !important;
  font-weight: bold!important;
  box-shadow: inset 0px 0px 5em 0px rgba(255,255,255,.5) !important;
}




:root {
  --tabs_toolbar_color_tabs_not_on_top: linear-gradient(#f9f9fa,#f9f9fa);
  --tabs_toolbar_border-tnot_normal_mode_size: 1px;
  --tabs_toolbar_border-tnot_normal_mode: var(--tabs-border-color);
  --classic_squared_tabs_tab_text_color: black;
  --classic_squared_tabs_tab_text_shadow: transparent;
  --tab-min-height_tnot: 32px;
}

:root[uidensity=compact]  {
  --tab-min-height_tnot: 28px;
}

:root[uidensity=touch] {
  --tab-min-height_tnot: 40px;
}

/* tabs toolbar adjustment */
#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#TabsToolbar {
  -moz-padding-start: 2px !important;
}

#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[uidensity=compact][tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#TabsToolbar:-moz-lwtheme,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[sizemode="maximized"] #TabsToolbar,
#main-window[tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #TabsToolbar {
  -moz-padding-start: 0px !important;
}

#main-window[tabsintitlebar][sizemode="normal"]:not([sizemode="fullscreen"]) #TabsToolbar {
  margin-top: 0px !important;
}

#main-window[tabsintitlebar][sizemode="normal"][chromehidden~="menubar"] #TabsToolbar,
#main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"][chromehidden~="menubar"] #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar {
  padding-top: 0px !important;
}

#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"]:not([inactive="true"]) ~ #TabsToolbar,
#main-window[tabsintitlebar] #toolbar-menubar[autohide="false"] ~ #TabsToolbar{
  margin-top: 0px !important;
}

/* tab title in titlebar support */
#main-window[tabsintitlebar][sizemode="normal"] #navigator-toolbox #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="normal"] #navigator-toolbox #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #navigator-toolbox #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #navigator-toolbox #TabsToolbar,
#main-window[tabsintitlebar][sizemode="normal"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="normal"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar{
  margin-top: 0px !important;
}


/* fix for application/hamburger button in titlebar */
#main-window[tabsintitlebar][sizemode="fullscreen"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #nav-bar  #PanelUI-button {
  visibility: collapse !important;
}

#main-window[inDOMFullscreen="true"] #TabsToolbar {
  opacity: 0 !important;
}

/* tab height */
#tabbrowser-tabs,
#tabbrowser-tabs > .tabbrowser-arrowscrollbox,
.tabbrowser-tabs[positionpinnedtabs] > .tabbrowser-tab[pinned] {
  min-height: var(--tab-min-height_tnot) !important;
}

/* toolbar order (start) ************************************/
#print-preview-toolbar,
#printedit-toolbar,
#titlebar {
  -moz-box-ordinal-group: 0 !important;
}
#navigator-toolbox #toolbar-menubar {
  -moz-box-ordinal-group: 1 !important;
}
/* navigation toolbar */
#navigator-toolbox #nav-bar {
  -moz-box-ordinal-group: 2 !important;
}
/* bookmarks toolbar */
#navigator-toolbox #PersonalToolbar {
  -moz-box-ordinal-group: 3 !important;
}
/* 3rd party toolbars */
#navigator-toolbox toolbar {
  -moz-box-ordinal-group: 10 !important;
}
/* tabs toolbar */
#navigator-toolbox #TabsToolbar {
  -moz-box-ordinal-group: 100 !important;
}
/* toolbar order (end) **************************************/


/* toolbar borders */
#main-window #navigator-toolbox::after {
  opacity: 0 !important;
}

#TabsToolbar{
  margin-bottom: 0px !important;
  border-bottom: 1px solid #5f7181 !important;
  display: block !important;
}

#main-window[sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
  border-left: var(--tabs_toolbar_border-tnot_normal_mode_size) solid var(--tabs_toolbar_border-tnot_normal_mode) !important;
  border-right: var(--tabs_toolbar_border-tnot_normal_mode_size) solid var(--tabs_toolbar_border-tnot_normal_mode) !important;
  background-clip: padding-box !important;
}

#main-window[sizemode="maximized"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
  border-left: 0px !important;
  border-right: 0px !important;
}

#main-window[style*='--lwt-header-image'][sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar):-moz-lwtheme,
#main-window[style*='--lwt-header-image'][sizemode="maximized"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar):-moz-lwtheme {
  border-top: 0px !important;
  border-left: 0px !important;
  border-right: 0px !important;
}

#main-window:not([style*='--lwt-header-image']):-moz-lwtheme-brighttext #TabsToolbar:-moz-lwtheme {
  border-bottom: 1px solid #323234 !important;
}

#main-window:not([style*='--lwt-header-image']):-moz-lwtheme:-moz-lwtheme-brighttext #TabsToolbar:-moz-lwtheme {
  border-bottom: 1px solid #323234 !important;
}

#main-window:not([sizemode="fullscreen"])[tabsintitlebar] #TabsToolbar{
  -moz-margin-end: 0px !important;
}

#main-window[tabsintitlebar] #TabsToolbar .titlebar-placeholder{
  visibility: collapse !important;
}

#main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive="true"] {
  margin-top: 21px !important;
}
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] {
  margin-top: 20px !important;
}

#tabbrowser-tabs .tab-drop-indicator {
  margin-bottom: 0px !important;
}


/* remove tab fog */
#TabsToolbar:not(:-moz-lwtheme),
#TabsToolbar:not(:-moz-lwtheme)::before,
#TabsToolbar:not(:-moz-lwtheme)::after {
  box-shadow: unset !important;
  display: block !important;
}

/* remove 'dragging tab' margin/padding nonsense */
#TabsToolbar[movingtab] {
  padding-bottom: unset !important;
}

#TabsToolbar[movingtab] > .tabbrowser-tabs {
  padding-bottom: unset !important;
  margin-bottom: unset !important;
}

#TabsToolbar[movingtab] + #nav-bar {
  margin-top: unset !important;
}

/* scroll buttons */
#TabsToolbar:not(:-moz-lwtheme) #alltabs-button,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-arrowscrollbox > .scrollbutton-up,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-arrowscrollbox > .scrollbutton-down {
  fill: black !important;
}

/* Fx58+ titlebar placeholders */
#TabsToolbar .titlebar-placeholder[type="pre-tabs"],
#TabsToolbar .titlebar-placeholder[type="post-tabs"]{
  display: none !important;
}

@media (-moz-os-version: windows-win10) {
    #main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive="true"] {
      margin-top: 30px !important;
    }
    #main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] {
      margin-top: 30px !important;
    }
}

@media (-moz-windows-classic) {

    /* tweaks for Windows Classic theme */
    #nav-bar:not(:-moz-lwtheme),
    #PersonalToolbar:not(:-moz-lwtheme),
    #main-window:not([tabsintitlebar])  #TabsToolbar:not(:-moz-lwtheme) {
      border-left: unset !important;
      border-right: unset !important;
      background: unset !important;
    }

    #main-window[sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
      border-left: 0px !important;
      border-right: 0px !important;
    }

    #main-window:not([tabsintitlebar]) #toolbar-menubar:not(:-moz-lwtheme) {
      background: unset !important;
      box-shadow: unset !important;
      border-bottom: unset !important;
    }

    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox,
    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar,
    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox::before,
    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar::before,
    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox::after,
    #main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar::after {
      background: unset !important;
      box-shadow: unset !important;
      border: unset !important;
      border-image: unset !important;
    }

    #main-window:not([tabsintitlebar]) toolbar:not(#TabsToolbar):not(#toolbar-menubar):not(#nav-bar):not(:-moz-lwtheme) {
      background: unset !important;
    }

}


/* fix Windows 7s default tab background (remove dark purple bg color)*/
@media (-moz-os-version: windows-win7) {
  @media (-moz-windows-default-theme) {
    .tabbrowser-tab:not([selected]):not(:hover):not(:-moz-lwtheme) {
      background-color: #e3e4e6 !important;
    }
    .tabbrowser-tab:not([selected]):hover:not(:-moz-lwtheme) {
      background-color: #cccdcf !important;
    }

  }
}