nix/modules/programs/home/firefox/userChrome

#alltabs-button { display: none !important; }
@namespace xul "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";

:root {
    --background: #1d2021;
    --secondary: #282828;
    --foreground: #EBDBB2;
    --orange-highlight: #fe8019;
    --sound-border: #68217A;
    --separator: #665e54;
    --toolbar-bgcolor: var(--secondary) !important;
    --tab: var(--background);
    --tab-btn: var(--tab-inactive);
    --tab-inactive: var(--secondary);
    --tab-btn-inactive: var(--tab-inactive);
    --tab-hover: #32302f;
    --tab-btn-hover: #3C3836;
    --toolbar-btn-hover: #49463f;
    --url-bar: #3C3836; /* Updated color */
    --url-focus: #3C3836;
    --url-bar-item-hover: #6a6257;
    --sidebar: #3C3836;
    --sidebar-button-hover: #5A544B;
    --sidebar-highlight: #458588;
}

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

.panel-arrowcontainer {
    background-color: var(--secondary) !important;
}

#PopupAutoComplete,
#PopupSearchAutoComplete {
    background-color: var(--url-focus) !important;
    color: var(--foreground) !important;
}

panelview {
    background-color: var(--sidebar) !important;
    color: var(--foreground) !important;
}

panel[type="autocomplete-richlistbox"] {
    --panel-background: none !important;
    border-radius: 4px !important;
    color: var(--foreground) !important;
}

toolbarseparator,
menuseparator {
    border-color: var(--separator) !important;
    border-image: none !important;
}

toolbar {
    background-color: var(--secondary);
}

toolbar#TabsToolbar {
    background-color: var(--background);
}

toolbar#TabsToolbar:-moz-window-inactive {
    background-color: var(--toolbar-bgcolor) !important;
}

#titlebar,
#titlebar-spacer,
#titlebar-buttonbox-container {
    background-color: var(--background) !important;
    border: none !important;
}

#navigator-toolbox {
    --tabs-border-color: var(--orange-highlight) !important;
}

#navigator-toolbox::after {
    border-bottom: 0px !important;
}

#navigator-toolbox {
    border: none !important;
}

#urlbar,
#searchbar {
    box-shadow: none !important;
    border: none !important;
    border-radius: 4px;
    color: var(--foreground) !important;
    background-color: var(--url-bar) !important;
    --autocomplete-popup-separator-color: var(--separator) !important;
}

#urlbar-input,
#urlbar-input-container {
    color: var(--foreground) !important;
    background-color: var(--url-bar) !important;
}

#urlbar:not([open]) #urlbar-input-container:focus-within,
#searchbar:focus-within {
    border: 2px solid var(--orange-highlight) !important;
}

#urlbar:focus-within,
#urlbar[open],
#urlbar[open] #urlbar-input-container,
#urlbar[open] #urlbar-input,
#urlbar-input-container:focus-within,
#urlbar-input:focus,
#urlbar-background,
.urlbarView,
#searchbar:focus-within,
menupop {
    background-color: var(--url-focus) !important;
}

#searchbar:focus-within {
    outline: none !important;
}

:is(panel, menupopup)::part(content) {
    background: none !important;
}

.urlbarView button:hover,
#searchbar button:hover,
.urlbarView-row:hover .urlbarView-row-inner,
.search-autocomplete-richlistbox-popup .autocomplete-richlistitem:hover {
    background-color: var(--url-bar-item-hover) !important;
}

.urlbarView-row[type="switchtab"] > span {
    color: var(--orange-highlight) !important;
}

#PopupSearchAutoComplete .autocomplete-richlistitem[selected],
.searchbar-engine-one-off-item[selected],
.urlbarView-row[selected],
.urlbarView-row[aria-selected="true"],
.urlbarView-row:not([type="tip"], [type="dynamic"])[selected] > .urlbarView-row-inner,
.urlbarView-row-inner[selected] {
    color: var(--foreground) !important;
    background-color: var(--sidebar-highlight) !important;
    border-radius: 4px !important;
}

#PersonalToolbar {
    background-color: var(--secondary) !important;
}

.tab-background[selected="true"] {
    background-color: transparent !important;
    background-image: none !important;
}

.tabbrowser-tab:hover > .tab-stack > .tab-background:not([selected="true"]):not([multiselected]) {
    background-color: transparent !important;
}

.tabbrowser-tab[soundplaying="true"] {
    --lwt-tab-line-color: var(--sound-border) !important;
}

.tab-content[selected="true"] {
    border-color: var(--orange-highlight) !important;
    --sound-border: var(--orange-highlight) !important;
}

.tab-text {
    color: var(--foreground);
}

tab,
#tabbrowser-tabs {
    background-color: var(--background) !important;
    color: var(--foreground) !important;
}

tab:-moz-window-inactive,
#tabbrowser-tabs:-moz-window-inactive,
#nav-bar-customization-target {
    background-color: var(--secondary) !important;
}

.tabbrowser-tab[selected] {
    opacity: 1;
}

.tab-loading-burst {
    background-color: inherit;
}

.tab-content {
    border-radius: 4px;
    margin: 5px 0px 5px 0px !important;
    border: 1px solid transparent !important;
}

.tab-content[selected="true"] {
    background-color: var(--secondary) !important;
    color: var(--foreground) !important;
    border: 1px solid var(--orange-highlight) !important;
}

.tab-content:not([selected="true"]):hover {
    background-color: var(--tab-hover) !important;
}

toolbarbutton {
    fill: var(--foreground) !important;
    background-color: transparent !important;
}

#TabsToolbar toolbarbutton {
    border-radius: 4px;
    border: 1px solid transparent !important;
}

#alltabs-button > .toolbarbutton-badge-stack,
#tabs-newtab-button > .toolbarbutton-icon {
    background-image: none;
    border-radius: 6px;
}

#alltabs-button:hover > .toolbarbutton-badge-stack,
#tabs-newtab-button:hover > .toolbarbutton-icon {
    background-color: var(--tab-btn-hover) !important;
}

#TabsToolbar #firefox-view-button > .toolbarbutton-icon {
    background-image: none !important;
    border-radius: 4px;
}

#TabsToolbar #firefox-view-button[open] > .toolbarbutton-icon {
    background-color: var(--secondary) !important;
    color: var(--foreground) !important;
    padding: 9px !important;
    border: 1px solid var(--orange-highlight) !important;
}

#TabsToolbar #firefox-view-button:not([open]):hover > .toolbarbutton-icon {
    background-color: var(--tab-hover) !important;
}

#nav-bar toolbarbutton > .toolbarbutton-icon,
#nav-bar toolbarbutton > .toolbarbutton-badge-stack {
    border-radius: 6px;
}

#nav-bar toolbarbutton:hover > .toolbarbutton-icon,
#nav-bar toolbarbutton:hover > .toolbarbutton-badge-stack {
    background-color: var(--toolbar-btn-hover) !important;
}

#back-button {
    padding-right: 2px !important;
    padding-left: 2px !important;
    margin-left: 6px !important;
}

#PanelUI-menu-button {
    background-color: var(--secondary) !important;
    padding-right: 2px !important;
    margin-right: 6px !important;
}

#PersonalToolbar toolbarbutton {
    margin: 3px 0px 3px 3px !important;
    border-radius: 4px;
}

#PersonalToolbar toolbarbutton:hover {
    background-color: var(--toolbar-btn-hover) !important;
}