firefox.css

@namespace html url(http://www.w3.org/1999/xhtml);
@namespace xul url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
:root {
/* TAB VARIABLES */
--bg-light: #262626; --bg-dark: #222;
--fg-light: #A8D7CA; --fg-dark: #82A69C;
--tab-triangle-correction: -1px;
--tab-height: 30px; --tab-icon-size: 15px; --tab-strip-margin: 0px; --tab-overlap: -5px;
--tab-fonts: "Ubuntu","Sans Regular", "Sans Regular", "Sans Regular",monospace,"Sans Regular"; --tab-font-size: 11pt;
--tab-triangle: none;

/* URL VARIABLES */
--url-background: var(--bg-light); --url-color: var(--fg-dark);
--url-height: 23px; --url-right-margin: 5px;
--url-fonts: "Open Sans Light", "Sans Regular", "Sans Regular",monospace,"Sans Regular"; --url-font-size: 12pt;
--url-text-align: center;
--url-position: absolute;
}

@-moz-document url(chrome://browser/content/browser.xul) {
/* URL-BAR */



  #PanelUI-button {
    position: absolute;
    top: -30px;
    right: 5px;
    z-index: 100;
    outline: none !important;
  }



#bookmarks-menu-button, #home-button, #stylish-toolbar-button,
#abp-toolbarbutton, #back-button, #forward-button, #identity-box, #urlbar-reload-button,
#urlbar-stop-button, #urlbar-go-button, #notification-popup-box, #new-tab-button,
#private-browsing-indicator, #search-container, #nav-bar-overflow-button,
.tabs-newtab-button, .tab-close-button, .tab-close, .tab-throbber, .tab-background-start, .tab-background-end
 { display: none !important; }

.tab-drop-indicator { margin-bottom: 0 !important; }

#nav-bar {
position: var(--url-position) !important; bottom: 0 !important;
width: 100% !important; height: var(--url-height) !important;
min-height: var(--url-height) !important; max-height: var(--url-height) !important;
margin: 0 0 0 0 !important;

/* --- Uncomment the section below to attach the url-bar to the tab-bar [EXPERIMENTAL] (Require a line in "#TabsToolbar" below) --- */
/*
position: fixed !important; top: 0 !important; left: 0 !important;
width: 315px !important; max-width: 315px !important;
z-index: 100 !important;
*/
}
#nav-bar-customization-target { width: 100% !important; }
#urlbar-wrapper {
width: 102% !important; margin-top: -1px !important;
margin-left: -14pt !important;
position: absolute !important; top: 0 !important; left: 0 !important;
}
#urlbar {
border: none !important; border-radius: 0 !important;
margin: 0 0 0 0 !important; padding: 0 2px 0 9px !important;
height: var(--url-height) !important; min-height: var(--url-height) !important;
background: var(--url-background) !important; color: var(--url-color) !important;
font-family: var(--url-fonts) !important; font-size: var(--url-font-size) !important;
width: calc(100% + var(--url-right-margin)) !important; text-align: var(--url-text-align) !important;
outline: none !important;
}

/* --- Comment out the section below to make the url-bar visible --- */
/*#nav-bar {
width: 0 !important; height: 0 !important;
overflow: hidden !important;
position: fixed !important; left: -1px !important; top: -1px !important;
visibility: hidden !important;*/

}
/**/

/* (Uncomment the urlbar is placed on bottom) */
/* findbar { margin-bottom: var(--url-height) !important; } */


/* TABS */
.tabbrowser-tab[fadein]:not([pinned]) { min-width: 100px !important; max-width: 160px /*100%*/ !important; }
tab {
font-family: var(--tab-fonts) !important;
min-height: var(--tab-height) !important; height: var(--tab-height) !important;
background: var(--bg-dark) !important; color: var(--fg-dark) !important;
font-size: var(--tab-font-size); text-shadow: none !important; text-align: left /* center | left */ !important;
}

.tabbrowser-tab label { padding: 0 15px 0 15px !important; }

#tabbrowser-tabs .tabbrowser-tab[pinned]            { width: 55px !important; }
#tabbrowser-tabs .tabbrowser-tab[pinned] label      { display: none !important; }

#tabbrowser-tabs .tabbrowser-tab .tab-icon-image {
margin: 0 -10px 0 5px !important;
width: var(--tab-icon-size) !important;
height: var(--tab-icon-size) !important;
}

.tabbrowser-tab *, .tabs-newtab-button * {
background: none !important; list-style-image: none !important;
margin: 0 0 0 0 !important; padding: 0 0 0 0 !important;
-moz-appearance: none !important;
margin: 0px /* 1px */ !important;
}

#tabbrowser-tabs .tabbrowser-tab[pinned] .tab-stack { height: var(--tab-height) !important; width: 100% !important; }
#tabbrowser-tabs .tabbrowser-arrowscrollbox .box-inherit.scrollbox-innerbox { max-height: var(--tab-height) !important; }
.scrollbutton-up, .scrollbutton-down { border: none !important; }

.tabbrowser-tab[selected="true"] .tab-stack {
background: var(--bg-light) !important; color: var(--fg-light) !important;
border-radius: 0px !important; position: relative !important; margin: 0px /* 1px */ !important;
border-top: 3px solid #8c8c8c !important;
}
.tabbrowser-tab[selected="true"]:before { /* Left Triangle (of selected tab) */
display: var(--tab-triangle); content: '' !important; position: absolute !important; z-index: 2 !important;
top: 0 !important; left: var(--tab-overlap) !important; width: 0 !important; height: 0 !important;
border: none !important;

/*border-left: calc(var(--tab-height)/2) solid var(--bg-dark) !important;
border-top: calc((var(--tab-height)/2) - var(--tab-triangle-correction)) solid var(--bg-light) !important;
border-bottom: calc((var(--tab-height)/2) + var(--tab-triangle-correction)) solid var(--bg-light) !important;*/
border-top: var(--tab-height) solid var(--bg-dark) !important;
border-right: calc(var(--tab-height)/2) solid var(--bg-light) !important;
}
.tabbrowser-tab[selected="true"]:after { /* Right Triangle (of selected tab) */
display: var(--tab-triangle); content: '' !important; position: absolute !important; z-index: 2 !important;
top: 0 !important; right: var(--tab-overlap) !important; width: 0 !important; height: 0 !important;
border: none !important;

/*border-right: calc(var(--tab-height)/2) solid var(--bg-dark) !important;
border-top: calc((var(--tab-height)/2) - var(--tab-triangle-correction)) solid var(--bg-light) !important;
border-bottom: calc((var(--tab-height)/2) + var(--tab-triangle-correction)) solid var(--bg-light) !important;*/
border-top: var(--tab-height) solid var(--bg-dark) !important;
border-left: calc(var(--tab-height)/2) solid var(--bg-light) !important;
}

#TabsToolbar, #tabbrowser-tabs {
-moz-appearance: none !important;
height: var(--tab-height) !important; min-height: var(--tab-height)!important;
margin-left: var(--tab-strip-margin) !important; margin-right: var(--tab-strip-margin) !important;
background: var(--bg-dark) !important;

/* --- Uncomment the line below to attach the url-bar to the tab-bar [EXPERIMENTAL] (Require a line in "#nav-bar" above) --- */
/*margin-left: 150px !important;*/
}
#TabsToolbar::after { display: none !important; }
.tabbrowser-tab::before, .tabbrowser-tab::after { background: none !important; }

/*browser, #navigator-toolbox { -moz-appearance: none !important; background: transparent !important; }*/

#navigator-toolbox::after { height: 3px !important; background: var(--bg-light) !important; }
#liberator-separator { height: 3px !important; background: var(--bg-light) !important; }

/* MENUS */
menuitem + menuseparator, menu + menuseparator, .menu-iconic-left  { display: none !important; }
menuitem > label { margin-left: var(--tab-height) !important; }
menubar, menubutton, menulist, menu, menuitem {
font-family: var(--tab-fonts) !important; font-size: var(--tab-font-size);
height: var(--tab-height) !important;
}

/* HIDE ORANGE MENU BUTTON */
#appmenu-toolbar-button, #appmenu-button-container { display: none !important; }

/* HIDE STATUS BAR */
#status-bar, #statusbar-display, statuspanel { display: none !important; }

/* PRIVATE BROWSING ICON HIDE */
#main-window[privatebrowsingmode=temporary] #private-browsing-indicator,
#main-window[privatebrowsingmode=temporary] #private-browsing-indicator-titlebar { display: none !important; }

/* Vimperator icon style */
#liberator-statusline:not([customizing="true"]) { margin: -2px -2px !important; padding: 0 0 !important; height: 24px !important; }
#liberator-statusline:not([customizing="true"]) :-moz-any(toolbarbutton) { height: 100% !important; }
#tabview-button {
list-style-image: url(http://twily.info/img/tabview-button.png?v=2) /* 16x16 px image */ !important;
-moz-image-region: rect(0, 0, 0, 0) !important;
}

/* Tabgroup margin top fix */
#tab-view-deck #tab-view { margin-top: 11px !important; }
#tab-view-deck { background: var(--bg-light) !important; }

/* Tab Group Page Style (Ctrl+Shift+E) */
@-moz-document url(chrome://browser/content/tabview.html) {
#content #bg, #actions, body { background: var(--bg-light) !important; }
body * { color: var(--fg-light) !important; }

body .groupItem, #content #actions, body .undo {
background: var(--bg-dark) !important;
border: 0 !important; border-radius: 0 !important; box-shadow: 0 0 0 0 !important;
}
#content #actions {
opacity: 0 !important; display: none !important; /* block | none */
transition: .3s ease-out !important;
}
#content #actions:hover { opacity: 1 !important; }

body .appTabTrayContainer { border: 0 !important; }
body .tab, body .tab .thumb {
box-shadow: 0 0 0 0 !important; border: 0 !important; border-radius: 0 !important;
background: transparent !important; padding : 0 !important;
}
body .tab .favicon { display: none !important; }
body .groupItem .name { border: 0 !important; }
body .tab .tab-title { padding-top: 2px !important; }
}


/* AGENT_SHEET */
@-moz-document url-prefix(http://), url-prefix(https://), url-prefix(chrome://liberator/) {



/* SCROLLBAR */
scrollbar[orient="vertical"], scrollbar thumb[orient="vertical"],
scrollbar[orient="horizontal"], scrollbar thumb[orient="horizontal"] {
display: block !important;
}


  scrollbar {
    color: red;
    background-color: blue;
  }


/* background color around/behind pictures opened in firefox (require html namespace on top) */
@-moz-document regexp("(https?://|file:///)(.*)\\.(jpeg|jpg|gif|png|apng|svg|bmp|webm|webp)") {
body { background: var(--bg-light) !important; }
}


/* About:Blank background */
@-moz-document url(about:blank) {
html,body { background: var(--bg-light) !important; }
}

/* about:stylish-edit toolbar style */
@-moz-document regexp("about:stylish-edit.*") {
#main-area, textbox { background: var(--bg-light) !important; }
textbox, grid, columns, rows, separator { border: 0 !important; }

.devtools-toolbarbutton { background: var(--bg-dark) !important; color: var(--fg-light) !important; }
}

/*----- Fix for white flash on new tab -----*/
tabbrowser tabpanels, #appcontent > #content { background: var(--bg-light) !important; }


/* Set dark text in light textareas
@-moz-document regexp("https?://(?!(localhost|twily.info|.*.4chan.org|.*.youtube.com)).*") {
input, textarea { color: #222628 !important; -moz-appearance: none !important; }
}*/