diff --git a/firefox/README.md b/firefox/README.md
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+Firefox configuration
+=========
+
+- Configure Firefox Sync if needed
+- Change to dark theme and compact density in Customize and Tree Style Tab config
+
+Add-ons
+------
+
+- [Awesome RSS](https://addons.mozilla.org/en-US/firefox/addon/awesome-rss/)
+- [Display inline](https://addons.mozilla.org/en-US/firefox/addon/display-inline/)
+- [PassFF](https://addons.mozilla.org/en-US/firefox/search/)
+- [Tree Style Tab](https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/)
+- [Tridactyl](https://addons.mozilla.org/en-US/firefox/addon/tridactyl-vim/)
+- [uBlock Origin](https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/)
+- [Vue.js devtools](https://addons.mozilla.org/en-US/firefox/addon/vue-js-devtools/)
+- [Wallabager](https://addons.mozilla.org/en-US/firefox/addon/wallabagger/)
+- [Tampermonkey](https://addons.mozilla.org/en-US/firefox/addon/tampermonkey/)
+
+userChrome.css
+----------
+
+Move the [userChrome.css](userChrome.css) file in `%{PROFILE_PATH}/chrome/`.
+
+Search engines
+--------
+
+Add search engines:
+- [Qwant](https://www.qwant.com/) (keyword: q)
+- [DuckDuckGo](https://duckduckgo.com/) (keyword: duck)
+- [Startpage](https://www.startpage.com/) (keyword: s)
+- [Google](https://www.google.com/) (keyword: gg)
+- [Wikipedia FR](https://fr.wikipedia.org/) (keyword: wf)
+- [Wikipedia EN](https://en.wikipedia.org/) (keyword: we)
diff --git a/firefox/userChrome.css b/firefox/userChrome.css
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+/* Hide horizontal tabs at the top of the window */
+#main-window[tabsintitlebar="true"]:not([extradragspace="true"]) #TabsToolbar {
+  opacity: 0;
+  pointer-events: none;
+}
+#main-window:not([tabsintitlebar="true"]) #TabsToolbar {
+  visibility: collapse !important;
+}
+
+/* Hide the "Tree Style Tab" header at the top of the sidebar */
+#sidebar-box[sidebarcommand="treestyletab_piro_sakura_ne_jp-sidebar-action"] #sidebar-header {
+  display: none;
+}