#navigator-toolbox {
    -moz-appearance: none;
    border-top: none;
}

.browser-toolbar:not(.titlebar-color),
#tabbrowser-tabs:not([movingtab])
                    > .tabbrowser-arrowscrollbox
                    > .tabbrowser-tab
                    > .tab-stack
                    > .tab-background[multiselected='true']:-moz-lwtheme,
#tabbrowser-tabs:not([movingtab])
                    > .tabbrowser-arrowscrollbox
                    > .tabbrowser-tab
                    > .tab-stack
                    > .tab-background[selected='true']:-moz-lwtheme,
box {
    background-image: none !important;
}
* {
    --tab-min-width: 76px;
}


#urlbar:not(.megabar):not([focused='true']):-moz-lwtheme,
#urlbar.megabar:not([focused='true']):-moz-lwtheme > #urlbar-background,
#navigator-toolbox #searchbar:not(:focus-within):-moz-lwtheme,
#navigator-toolbox {
    border: none !important;
}

toolbox {
    z-index: 10;
    margin-top: 0px !important;
    margin-bottom: -30px !important;
    height: 0 !important;
}

#nav-bar {
    visibility: hidden;
    transition: visibility 1s !important;
}


#titlebar:hover + #nav-bar,
#nav-bar:focus-within {
    visibility: visible;
}

#navigator-toolbox {
    -moz-appearance: none;
    border-top: none;
}

.browser-toolbar:not(.titlebar-color),
#tabbrowser-tabs:not([movingtab])
                    > .tabbrowser-arrowscrollbox
                    > .tabbrowser-tab
                    > .tab-stack
                    > .tab-background[multiselected='true']:-moz-lwtheme,
#tabbrowser-tabs:not([movingtab])
                    > .tabbrowser-arrowscrollbox
                    > .tabbrowser-tab
                    > .tab-stack
                    > .tab-background[selected='true']:-moz-lwtheme,
box {
    background-image: none !important;
}
* {
    --tab-min-width: 76px;
}


#urlbar:not(.megabar):not([focused='true']):-moz-lwtheme,
#urlbar.megabar:not([focused='true']):-moz-lwtheme > #urlbar-background,
#navigator-toolbox #searchbar:not(:focus-within):-moz-lwtheme,
#navigator-toolbox {
    border: none !important;
}

toolbox {
    z-index: 10;
    margin-top: 0px !important;
    margin-bottom: -30px !important;
    height: 0 !important;
}

#nav-bar {
    visibility: hidden;
    transition: visibility 1s !important;
}


#titlebar:hover + #nav-bar,
#nav-bar:hover,
#nav-bar:focus-within
{
    visibility: visible;
}

Fix navbar flashing in firefox
Fix navbar flashing in firefox
