How to remove tab bar for tree style tabs?

[nalston]

Not really a 'bug' per se. Im running tree style tabs, and would like to remove the top tab bar, while keeping the rest of the nordic theme in place (because i love it). Rather than taking hours of trial and error, hoping you can help me figure out how i can remove the top tab bar all together while keeping the rest of the theme.

https://imgur.com/a/OApUUl4

[llsaboya]

I use this to remove the tab bar in my customChrome.css, from this theme:

My Firefox Theme

/* TREE STYLE TABS */
@media all {
    /* Reduce minimum width of the sidebar */
    #sidebar {
        min-width: 100px !important;
    }

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

/* REMOVE TAB BAR */
@media all {
    /* :root[sizemode="maximized"][tabsintitlebar="true"] #navigator-toolbox {
        margin-top: 8px;
    } */
    #titlebar {
        -moz-appearance: none !important;
    }
    #TabsToolbar {
        visibility: collapse !important;
    }
}

#navigator-toolbox:-moz-lwtheme {
    --tabs-border-color: rgba(0,0,0,.1) !important;
}

/* #nav-bar-customization-target {
    flex: 1;
} */
#nav-bar > * {
    --toolbar-start-end-padding: 2px;
}