@media (-moz-bool-pref: "zen.tabs.vertical") {
  #titlebar {
    height: 100%;
  }
  
  #navigator-toolbox {
    --zen-tabbrowser-padding: 5px;
    margin-top: 0; /* Issue #156 */
  }
  
  :root[inFullscreen="true"] #navigator-toolbox {
    margin-top: 0 !important;
  }
  
  #zen-tabbox-wrapper:has(#zen-sidebar-splitter:not([state="dragging"])) #navigator-toolbox {
    transition: .3s;
  }
  
  #navigator-toolbox toolbar#TabsToolbar {
    margin: var(--zen-appcontent-separator-from-window);
    overflow: hidden;
    transition: .2s;
    flex-direction: column;
    padding: 5px 0;
    margin-right: 0;
    -moz-window-dragging: no-drag;
    --zen-sidebar-action-button-width: 38px;
    padding-bottom: calc(5px + 5px); /* Taking into consideration the padding of the sidebar without being inlined */
  }
  
  #TabsToolbar-customization-target {
    flex-direction: column;
    max-width: 100%;
  }
  
  :root[customizing] .customization-target:not(#widget-overflow-fixed-list) {
    min-width: 0;
  }
  
  toolbarpaletteitem {
    justify-content: center;
  }
  
  toolbarbutton#scrollbutton-down,
  toolbarbutton#scrollbutton-up {
    display: none;
  }
  
  #toolbar-menubar {
    display: none;
  }
  
  .tab-label-container {
    display: none;
  }
  
  .tab-icon-stack > .tab-icon-image,
  .tab-icon-stack > .tab-throbber {
    width: var(--zen-browser-tab-icon-size);
    height: var(--zen-browser-tab-icon-size);
    margin-inline-end: 0;
  }
  
  .tab-icon-stack .tab-icon-image {
    transform: scale(0.5);
    opacity: 0;
    animation: zen-zoom-in 0.12s ease-in-out 0.3s forwards;
  }
  
  .tab-background {
    display: none;
  }
  
  .tabbrowser-tab {
    --zen-browser-tab-icon-size: 18px;
    --tab-min-width: 36px;
    margin: 0 auto;
    border-radius: 8px;
    position: relative;
    color-scheme: var(--tab-selected-color-scheme);
    border: 2px solid transparent;
    background: transparent;
    padding: 0;
    align-items: center;
    min-height: var(--tab-min-width); /* Make a box */
    animation: zen-slide-in 0.3s;
    width: calc(var(--zen-browser-tab-icon-size) + 2px);
    transition: .1s background, .1s border-color;
    min-width: var(--tab-min-width);
    display: flex;
    justify-content: center;
    align-items: center;
  }
  
  @media (-moz-bool-pref: "zen.tabs.dim-pending") {
    .tabbrowser-tab[pending]:not(:hover) {
      opacity: 0.5;
    }
  }
  
  .tabbrowser-tab[hidden="true"] {
    display: none;
  }
  
  .tabbrowser-tab:hover {
    background: var(--toolbarbutton-hover-background);
  }
  
  .tabbrowser-tab:active,
  .zen-sidebar-panel-button:active {
    transform: scale(0.9);
  }
  
  .tab-stack {
    width: 30px;
    height: 30px;
    min-width: 30px;
    min-height: 30px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .tabbrowser-tab:not([fadein]) {
    display: none;
  }
  
  .tabbrowser-tab:is([multiselected="true"], [selected]) {
    background: var(--toolbarbutton-hover-background);
  }
  
  #private-browsing-indicator-with-label {
    display: none;
  }
  
  .tabbrowser-tab::after {/* Containers */
    background: var(--identity-tab-color, transparent);
    border-radius: 2px;
    height: 80%;
    width: 2px;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    left: -2px;
    content: '';
    pointer-events: none;
  }
  
  .tabbrowser-tab {
    margin-inline-start: 0;
    margin: 0 auto;
    margin-bottom: 1.5px;
  }
  
  .tabbrowser-tab[pinned] {
    position: relative;
    display: flex;
  }
  
  #tabbrowser-tabs:has(.tabbrowser-tab[pinned]) .tabbrowser-tab:nth-child(1 of [fadein]:not([pinned]):not([hidden])) {
    margin-top: 15px;
    position: relative;
    overflow: visible;
  
    & .tab-stack::before {
      content: '';
      position: absolute;
      top: -11px;
      left: 0;
      width: 100%;
      height: 1.5px;
      border-radius: 1px;
      background: var(--zen-colors-border);
    }
  }
  
  .tab-close-button {
    position: absolute;
    display: none;
    left: 0;
    top: 50%;
  }
  
  .tabbrowser-tab[open="true"]:hover .tab-close-button {
    /* TODO: fix this */
    /*display: block;*/
  }
  
  .tab-content {
    padding: 0;
    width: fit-content;

    &[pinned] {
      padding: 0 !important;
    }
  }
  
  .toolbar-items > toolbartabstop:first-child {
    display: none;
  }
  
  #nav-bar > *:not(.titlebar-buttonbox-container) {
    padding-top: 5px;
    padding-bottom: 5px;
  }
  
  #TabsToolbar-customization-target {
    height: 100%;
  }
  
  #tabbrowser-tabs {
    margin-inline-start: 0;
    padding-inline-start: 0;
    border: none;
    /*background: light-dark(rgba(0,0,0,.05), rgba(255,255,255,.05));*/
    margin: 0;
    border: none;
    height: 100%;

    padding-inline-start: 0 !important;
    margin-inline-start: 0 !important;
  }
  
  #tabbrowser-arrowscrollbox {
    margin: 3px 0;
  }
  
  #alltabs-button stack {
    transform: rotate(-90deg);
  }
  
  .tab-icon-overlay {
    margin-inline-end: 0;
    display: none; /* TODO: fix this */
  }

  @media (-moz-bool-pref: "zen.view.sidebar-collapsed.hide-mute-button") and (not (-moz-bool-pref: "zen.view.sidebar-expanded")) {
    .tab-icon-overlay:is([soundplaying], [muted]):not([selected]) {
      display: none;
    }
  }
  
  @media (-moz-bool-pref: "zen.view.sidebar-expanded") {  
    #navigator-toolbox:is([zen-user-hover="true"]:hover, :not([zen-user-hover="true"])) {
      --zen-navigation-toolbar-min-width: 155px;
      min-width: var(--zen-navigation-toolbar-min-width) !important;
      align-items: start;
      transition: .2s;
      width: 170px;
      border: none;
      padding-left: 2px;
    
      & .tab-label-container {
        display: block;
      }
    
      & #titlebar,
      & #TabsToolbar,
      & #TabsToolbar .toolbar-items {
        width: 100%;
        align-items: flex-start;
      }
    
      & #TabsToolbar > .toolbar-items toolbarbutton:not(#zen-workspaces-button) {
        width: 100% !important;
        border-radius: 8px;
      }
    
      & #TabsToolbar > .toolbar-items toolbarbutton:not(#zen-workspaces-button):hover {
        background: var(--button-hover-bgcolor);
      }
    
      & #TabsToolbar > .toolbar-items toolbarbutton:not(#zen-workspaces-button) .toolbarbutton-text,
      & #TabsToolbar > .toolbar-items toolbarbutton:not(#zen-workspaces-button) .toolbarbutton-icon,
      & #TabsToolbar > .toolbar-items toolbarbutton:not(#zen-workspaces-button) .toolbarbutton-badge-stack {
        background: transparent !important;
      }
    
      & #tabbrowser-arrowscrollbox-periphery > toolbarbutton {
        display: flex;
        justify-content: center;
        align-items: center;
      }

      & .tabbrowser-tab {
        max-width: unset !important;
    
        &:not([pinned]) {
          width: 100%;
        
          &:hover .tab-close-button {
            display: block !important;
          }
      
          & .tab-content {
            position: relative;
            width: 100%;
          }
          
          & .tab-stack {
            justify-content: start;
            padding: 10px;
            width: 100% !important;
          }
    
          & .tab-label-container {
        
            #tabbrowser-tabs:not([secondarytext-unsupported]) & {
              display: flex;
              align-items: center;
              padding-left: 10px;
            }
          }
        }
    
        &:active,
        .zen-sidebar-panel-button:active {
          transform: scale(0.96) !important;
        }
    
        &[pinned] {
          margin: 0 !important;
        }
      }

      & #tabbrowser-arrowscrollbox::part(scrollbox) {
        /* We have the pinned tabs on the top, next to each other,
        * and the rest of the tabs are below them. */
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(var(--tab-min-height), 1fr));
        padding: calc(var(--zen-tabbrowser-padding) / 2);
      }
    
      & .tabbrowser-tab:not([pinned]),
      & #tabbrowser-arrowscrollbox-periphery {
        grid-column: 1 / -1;
      }
    
      & .tabbrowser-tab[pinned] {
        grid-column: span 1;
        min-width: 100%;
      }
    
      & #zen-sidebar-icons-wrapper {
        width: -moz-available;
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(37px, 1fr));
        transition: .1s;
      }
    
      & #zen-sidebar-icons-wrapper::before {
        width: 100%;
      }
    }
  }

  @media not (-moz-bool-pref: "zen.view.sidebar-expanded") {
    #navigator-toolbox {
      width: fit-content !important;
    }
  }

  #navigator-toolbox[zen-user-hover="true"] {
    width: fit-content !important;
  } 

  /* Display the vertical tabs on the right side */
  @media (-moz-bool-pref: "zen.tabs.vertical.right-side") and (not (-moz-bool-pref: "zen.view.compact")) {
    #navigator-toolbox {
      order: 6;
      padding-left: 0;
    }

    #zen-sidebar-splitter {
      order: 5;
    }

    #tabbrowser-tabbox {
      padding-left: var(--zen-element-separation);
    }

    #tabbrowser-tabpanels .browserSidebarContainer {
      margin-right: 0 !important;
    }
  }

  @media (-moz-bool-pref: "zen.view.sidebar-expanded.on-hover") and (not (-moz-bool-pref: "zen.view.compact")) {
    #zen-sidebar-splitter {
      display: none !important;
    }

    #navigator-toolbox {
      z-index: 1;
    }

    #TabsToolbar {
      --hovered-verticaltab-width: 20em;

      transition: 200ms, margin 200ms, border-color 0 ease-in-out !important;
      z-index: 1;
      background-repeat: no-repeat !important;
      background-position: center center !important;
      background-size: cover !important;

      border-top: 1px solid transparent;
      border-right: 1px solid transparent;

      height: 100%;

      border-top-right-radius: var(--zen-border-radius);
      transform: translateY(-1px);
    }
    
    #navigator-toolbox:not(:hover) #TabsToolbar #tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab .tab-content[class] > .tab-close-button[class] {
      display: none !important;
      visibility: hidden !important;
    }

    #TabsToolbar-customization-target:hover > .toolbarbutton-1 > .toolbarbutton-text {
      transition-delay: 0.2s !important;
    }
    
    #TabsToolbar-customization-target:hover > .toolbarbutton-1 > .toolbarbutton-text {
      transition-delay: 0.2s !important;
    }
        
    #navigator-toolbox:hover #TabsToolbar {
      z-index: 100 !important;
      width: 250px !important;
      background-color: var(--zen-dialog-background);
      border-top-color: var(--zen-colors-border);
      border-right-color: var(--zen-colors-border);
      padding-right: .1rem !important;
      position: absolute;
    }

    @media (-moz-bool-pref: "zen.tabs.vertical.right-side") {
      #navigator-toolbox:hover {
        --zen-navigation-toolbar-min-width: 0 !important;
        position: relative;
        padding: 0 !important;
      }
      
      #TabsToolbar {
        border-right: 0 !important;
        border-left: 1px solid transparent;
        border-top-right-radius: 0;
        border-top-left-radius: var(--zen-border-radius);

        right: 100%;
      }

      #navigator-toolbox:hover #TabsToolbar {
        border-left: 1px solid var(--zen-colors-border);
      }
    }
  }
}