@media (-moz-bool-pref: "zen.view.use-single-toolbar") {
    .browserSidebarContainer.deck-selected::before {
      content: "" !important;
      position: absolute !important;
      top: 0px !important;
      left: 0px !important;
      height: 4px !important; /* Height of the top background */
      max-width: 100% !important;
      width: var(--bar-pcent) !important; /* Ensure full width or customizable width */
      background-color: var(--bar-colour) !important; /* Solid color for the bar */
      border-radius: 0 2px 2px 0; /* Adjust this value to control the roundness of the ends */
      z-index: 1 !important;
      transition: width 0.5s ease-in-out, background 0.2s ease !important; /* Apply smooth transition on width and background */
    }    /* Current tab loading progress and muted status */
    
    
    .browserSidebarContainer.deck-selected:has([zen-glance-selected])::before,
    .browserSidebarContainer.deck-selected.zen-glance-overlay::before {
      max-width: calc(85%) !important;
      left: calc(15%/2) !important;
      border-radius: 6px !important;
    }
    
    .browserSidebarContainer.deck-selected.zen-glance-background::before {
      background: transparent !important;
      height: 0px !important;
    }
    
    :root {
      &:has(.tabbrowser-tab[selected][busy]) {
        --bar-colour: var(--zen-primary-color);
        --bar-pcent: 15%;
      }
      &:has(.tabbrowser-tab[selected][busy][pendingicon]) {
        --bar-colour: var(--zen-primary-color);
        --bar-pcent: 45%;
      }
      &:has(.tabbrowser-tab[selected][busy][pendingicon][progress]) {
        --bar-colour: var(--zen-primary-color);
        --bar-pcent: 85%;
      }
      &:has(.tabbrowser-tab[selected][busy][progress]) {
        --bar-colour: var(--zen-primary-color);
        --bar-pcent: 95%;
      }
      &:has(.tabbrowser-tab[selected][muted]:not([busy])) {
        --bar-colour: orangered;
        --bar-pcent: 100%;
        
        .browserSidebarContainer.deck-selected::before {
          border-radius: 0;
        }
      }
    }
  }