Tabs mit abgerundeten Ecken

/*.tabbrowser-tab:not([selected="true"]){*/
.tabbrowser-tab:not([selected]) {
    background: rgb(187,187,187) !important;
    border: 1px solid black !important;
    color: black !important;
    border-top-right-radius: 8px !important;
    border-top-left-radius: 8px !important;
    
    }
.tab-background[selected] {
    background: rgb(249,249,250) !important;
    border: 1px solid black !important;
    border-top-right-radius: 8px !important;
    border-top-left-radius: 8px !important;
    font-weight: bold !important;
    }

/* Firefox Quantum userChrome.css tweaks ************************************************/
/* Github: https://github.com/Aris-t2/CustomCSSforFx/blob/master/classic/css/tabs/default_tabs_round_top_borders.css */
/* geändert am 18.11.2019 vom EDV-Oldie *************************************************/


:root {
  --default_tab_border_roundness: 10px;
}

/* tab top border roundness */
#TabsToolbar .tabbrowser-tab,
#TabsToolbar .tabbrowser-tab .tab-stack,
#TabsToolbar .tabbrowser-tab .tab-background,
#TabsToolbar .tabbrowser-tab .tab-content {
  border-top-left-radius: var(--default_tab_border_roundness) !important;
  border-top-right-radius: var(--default_tab_border_roundness) !important;
}

#TabsToolbar .tabs-newtab-button {
  border-top-left-radius: var(--default_tab_border_roundness) !important;
  border-top-right-radius: var(--default_tab_border_roundness) !important;
}

/* hide tab separators */
.tabbrowser-tab::after,
.tabbrowser-tab::before {
  opacity: 0 !important;
  border-image: unset !important;
  border-image-slice: unset !important;
  width: unset !important;
}

#tabbrowser-tabs[movingtab] > .tabbrowser-tab[beforeselected]:not([last-visible-tab])::after,
.tabbrowser-tab:not([selected]):not([afterselected-visible]):not([afterhovered]):not([first-visible-tab]):not(:hover)::before,
#tabbrowser-tabs:not([overflow]) > .tabbrowser-tab[last-visible-tab]:not([selected]):not([beforehovered]):not(:hover)::after {
  content: unset !important;
  display: unset !important;
}

.tabbrowser-tab[selected],
.tab-background[selected] {
  color: white !important;
  border: 2px solid white !important;
}

.tabbrowser-tab:not([selected]){
  color: black!important;
  border: 1px solid gray !important;
}

.tabbrowser-tab[selected] .tab-content { 
    background: darkgray !important;
}

.tabbrowser-tab {
    margin-left: 3px !important;
}

#TabsToolbar .tab-close-button[selected="true"] {
    color: white !important;
}