@-moz-document url(chrome://browser/content/browser.xul), url(chrome://browser/content/browser.xhtml) {
    /* Hide main tabs toolbar */
    #TabsToolbar {
        visibility: collapse;
    }

    /* Sidebar min and max width removal */
    #sidebar {
        max-width: none !important;
        min-width: 0px !important;
    }

    /* Hide sidebar header, when using Tree Style Tab. */
    #sidebar-box[sidebarcommand="treestyletab_piro_sakura_ne_jp-sidebar-action"] #sidebar-header {
        visibility: collapse;
    }
}