Code Anpassung für Firefox 89

       /*Tableiste unten für normales Fenster*/
       
@-moz-document url(chrome://browser/content/browser.xhtml) {
       
#TabsToolbar {
    position: absolute !important;
    display: block !important;
    top: 107px !important; /*Abstand nach oben*/
    width: 100% !important;
    }
    
#tabbrowser-tabs {
    width: 100vw !important;
    }
        
#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
    padding-bottom: 34px !important;
    }

#TabsToolbar :is(.tabs-newtab-button,#tabs-newtab-button) {
   min-width: 0px !important;
   width: 25px !important;
   margin-bottom: 1px !important;
   margin-left: 1px !important;
   margin-top: 3px !important;
   fill: white !important;
   background: lightgrey !important;
   }
    
/*Damit wird der Tabtext am Ende nicht ausgeblendet*/    
.tab-label-container[textoverflow][labeldirection=ltr]:not([pinned]),
.tab-label-container[textoverflow]:not([labeldirection]):not([pinned]):-moz-locale-dir(ltr) {
    mask-image: none !important;
    }

:root {
   --tab-min-height: 32px !important; 
   }

:root #tabbrowser-tabs {
   --tab-min-height: 32px !important; 
   } 
}


                  /*Tableiste unten im privaten Fenster*/ 

/*Lila Icon oben rechts neben der Suchleiste*/
#main-window[privatebrowsingmode=temporary] #PanelUI-menu-button::before {
  margin-left: 0px!important;
  margin-right: 0px !important;
  content: '' !important;
  display: block !important;
  width: 19px !important;
  height: 19px !important;
  background: url("chrome://browser/skin/indicator-private-browsing.svg") !important;
  background-repeat: no-repeat !important;
  background-position: 0px 2px !important;
  background-size: 15px 15px !important;
}
    
#main-window[privatebrowsingmode=temporary] .private-browsing-indicator {
    display: none !important;
    }
    
#main-window[privatebrowsingmode=temporary] #TabsToolbar {
     position: absolute !important;
    display: block !important;
    top: 107px !important; /*Abstand nach oben*/
    width: 100% !important;
}
      
#main-window[privatebrowsingmode=temporary] .tab-line[multiselected], 
#main-window[privatebrowsingmode=temporary] .tab-line[selected="true"] {
    display: none !important;
    }

#main-window[privatebrowsingmode=temporary] .tabbrowser-tab:not([visuallyselected="true"]),
#main-window[privatebrowsingmode=temporary] .tabbrowser-tab[visuallyselected="true"] {
    margin-top: -4px !important;
    max-height: 40px !important; 
    }
    
#main-window[privatebrowsingmode=temporary] #tabbrowser-tabs {
    width: 100vw !important;
    }
        
#main-window[privatebrowsingmode=temporary]:not([chromehidden*="toolbar"]) #navigator-toolbox {
       padding-bottom: 34px !important;
    }
    
#main-window[privatebrowsingmode=temporary] #TabsToolbar :is(.tabs-newtab-button,#tabs-newtab-button) {
   min-width: 0px !important;
   width: 25px !important;
   margin-bottom: 1px !important;
   margin-left: 1px !important;
   margin-top: 3px !important;
   fill: white !important;
   background: lightgrey !important;
   }
    
/*Höhe der Tabs im privaten Fenster*/
#main-window[privatebrowsingmode=temporary]:root {
    --tab-min-height: 35px !important; 
    }
        
#main-window[privatebrowsingmode=temporary]:root #tabbrowser-tabs {
    --tab-min-height: 35px !important; 
    }
    
/*Damit wird der Tabtext am Ende nicht ausgeblendet*/    
#main-window[privatebrowsingmode=temporary] .tab-label-container[textoverflow][labeldirection=ltr]:not([pinned]),
#main-window[privatebrowsingmode=temporary] .tab-label-container[textoverflow]:not([labeldirection]):not([pinned]):-moz-locale-dir(ltr) {
    mask-image: none !important;
    }

:root {
    --tab-min-height: 32px !important; 
    }

:root #tabbrowser-tabs {
   --tab-min-height: 32px !important; 
   }

    /*Tableiste unten im privaten Fenster*/
    /*Lila Icon oben rechts*/
    #main-window[privatebrowsingmode=temporary] #PanelUI-menu-button.toolbarbutton-1 stack.toolbarbutton-badge-stack {
         padding-left: 30px !important;
         background: url("chrome://browser/skin/indicator-private-browsing.svg")no-repeat !important;
         }
         
    #main-window[privatebrowsingmode=temporary] .private-browsing-indicator {
        display: none !important;
        }
    #main-window[privatebrowsingmode=temporary] #TabsToolbar {
        position: absolute !important;
        display:block !important;
        top: 107px !important;
        width: 100vw !important;
        }
          
    #main-window[privatebrowsingmode=temporary] .tab-line[multiselected], .tab-line[selected="true"]{
        display: none !important;
        }
    #main-window[privatebrowsingmode=temporary] .tabbrowser-tab[visuallyselected="true"]{
        margin-top: -2px !important;
        max-height: 36px !important; 
        }
    #main-window[privatebrowsingmode=temporary] #tabbrowser-tabs {
        width: 100vw !important;
        }
            
    #main-window[privatebrowsingmode=temporary]:not([chromehidden*="toolbar"]) #navigator-toolbox {
        padding-bottom: var(--tab-min-height) !important;
        }
    /*Höhe der Tabs im privaten Fenster*/
    #main-window[privatebrowsingmode=temporary]:root {
        --tab-min-height: 35px !important; 
        }
            
    #main-window[privatebrowsingmode=temporary]:root #tabbrowser-tabs {
        --tab-min-height: 35px !important; 
        }
   
    /* Ab hier für normales Fenster*/
    @-moz-document url(chrome://browser/content/browser.xhtml) {
           
    #TabsToolbar {
        position: absolute !important;
        display:block !important;
        top: 107px !important;
        width: 100vw !important;
        }
    #tabbrowser-tabs {
        width: 100vw !important;
        }
            
    #main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
        padding-bottom: var(--tab-min-height) !important;
        }
    :root {
        --tab-min-height: 35px !important; 
        }
            
    :root #tabbrowser-tabs {
        --tab-min-height: 35px !important; 
        }
           
    /*Damit wird der Tabtext nicht ausgeblendet am Ende*/    
    .tab-label-container[textoverflow][labeldirection=ltr]:not([pinned]),
    .tab-label-container[textoverflow]:not([labeldirection]):not([pinned]):-moz-locale-dir(ltr) {
        mask-image: none !important;
        }
    }