#menubar-items{
   background: var(--v-main-menubar-background-color);
   color: black !important; /* черный цвет шрифта */ 
}
@-moz-document url("chrome://browser/content/browser.xhtml") {
:root {
    --v-main-menubar-min-height: 20px;
    --v-main-menubar-min-width: 15px;
    --v-main-menubar-color: rgb(0, 0, 0);
    --v-main-menubar-background-color: rgb(255, 255, 255);
    --v-main-menubar-background-color-hover: rgb(192, 192, 192);
    --v-main-menubar-background-color-active: rgb(192, 192, 192);
    &[uidensity="touch"] { /* мобильный режим */
        --v-main-menubar-min-height: 26px;
        --v-main-menubar-min-width: 21px;
    }
}

#titlebar {
    /* Классическое меню - показывать при наведении или при нажатии клавиши "Alt" --> */
    & > #toolbar-menubar[autohide="true"] #main-menubar > menu {
        appearance: none !important;
        border: none !important;
        border-radius: 0px !important;
        background: var(--v-main-menubar-background-color) !important;
        color: var(--v-main-menubar-color) !important;
        text-shadow: none !important;
        border-image: none !important;
        min-height: var(--v-main-menubar-min-height) !important;
        height: 1.25em !important;
    }
    & > #toolbar-menubar[autohide="true"] #menubar-items > #main-menubar {
        opacity: 0 !important;
        pointer-events: none !important;
        min-width: 0 !important;
        width: 0 !important;
        max-width: 0 !important;
        overflow: hidden !important;
    }
    & > #toolbar-menubar[autohide="true"] #menubar-items:hover > #main-menubar,
    & > #toolbar-menubar[autohide="true"]:not([inactive]) #menubar-items > #main-menubar {
        opacity: 1 !important;
        pointer-events: auto !important;
        width: auto !important;
        max-width: none !important;
    }
    :root:not([inFullscreen]) & > #toolbar-menubar[autohide="true"] #menubar-items {
        position: fixed !important;
        display: flex !important;
        flex-direction: row !important;
        align-items: center !important;
        top: auto !important;
        inset-inline-start: 0 !important;
        inset-inline-end: auto !important;
        z-index: 5 !important;
        visibility: visible !important;
        font-size: 12px !important;
    }
    & > #toolbar-menubar[autohide="true"] {
        visibility: visible !important;
        min-height: 0 !important;
        height: 0 !important;
        max-height: 0 !important;
        padding: 0 !important;
        margin: 0 !important;
        border: none !important;
        overflow: hidden !important;
    }
    & > #toolbar-menubar[autohide="true"] #main-menubar {
        appearance: none !important;
        background: none !important;
        border-radius: 0px !important;
        padding-block: 0 !important;
    }
    & > #toolbar-menubar[autohide="true"] #menubar-items::before {
        content: "F";
        display: flex;
        padding: 0px 2px;
        font: menu;
        font-weight: bold;
        font-style: normal;
        align-items: center;
        justify-content: center;
        cursor: default;
        background: var(--v-main-menubar-background-color);
        border-radius: 0px;
        color: var(--v-main-menubar-color);
        text-shadow: none;
        min-height: var(--v-main-menubar-min-height);
        min-width: calc(var(--v-main-menubar-min-width) - (var(--v-main-menubar-min-width) / 3));
        height: 1.25em;
        pointer-events: none;
        box-sizing: border-box;
    }
    & > #toolbar-menubar[autohide="true"] #menubar-items:hover::before,
    & > #toolbar-menubar[autohide="true"] #main-menubar > menu:not([disabled="true"]):is(:hover,[_moz-menuactive="true"]) {
        background: var(--v-main-menubar-background-color-hover) !important;
    }
    & > #toolbar-menubar[autohide="true"] #main-menubar > menu:not([disabled="true"]):is([open="true"],[checked="true"],:hover:active) {
        background: var(--v-main-menubar-background-color-active) !important;
    }
    & > #TabsToolbar :is(.titlebar-placeholder,.titlebar-spacer)[type="pre-tabs"] {
        font: menu !important;
        min-width: var(--v-main-menubar-min-width) !important;
        width: 1.1em !important;
    }
    :root:not([inFullscreen]) & > #toolbar-menubar[autohide="true"] + #TabsToolbar :is(.titlebar-placeholder,.titlebar-spacer)[type="pre-tabs"] {
        display: flex !important;
    }
    :root:not([inFullscreen]) & > #toolbar-menubar[autohide="true"]:not([inactive]) + #TabsToolbar > .titlebar-buttonbox-container {
        visibility: visible !important;
    }
    & > #toolbar-menubar[autohide="true"] + #TabsToolbar > .toolbar-items {
        padding-top: 0 !important;
        margin-top: 0 !important;
    }
    /* <-- Классическое меню - показывать при наведении или при нажатии клавиши "Alt" */
}
}

/* Добавляет отображение названия браузера в строке меню */
#main-menubar::after {
    display: flex;
    content: attr(version);
    height: 1.25em;
    min-height: var(--v-main-menubar-min-height, 1.25em);
    flex-direction: row;
    align-items: center;
    padding-inline-start: 6px;
    padding-inline-end: 6px;
    font-weight: bold !important;
    background: rgba(255,255,255);
    color: red !important; /* красеый цвет шрифта */
}