#tabbrowser-tabs {
  --uc-close-button-size: 24px;
  --uc-close-button-padding: 6px;
  --uc-close-button-margin: calc((var(--uc-close-button-size) - 16px) / -2);
}
#tabbrowser-tabs[closebuttons="activetab"] {
  --uc-close-button-size: 20px;
  --uc-close-button-padding: 4px;
}

@mixin pinnedCloseButtonShow($prefix: "") {
  #{$prefix}:not([busy]) .tab-close-button {
    display: -moz-box !important;
    -moz-box-ordinal-group: 0 !important;

    /* Looks like hover */
    width: var(--uc-close-button-size) !important;
    height: var(--uc-close-button-size) !important;
    padding: var(--uc-close-button-padding) !important;
    margin-inline: var(--uc-close-button-margin) !important;
  }
}
@mixin pinnedIconStackLayout($prefix: "") {
  #{$prefix}:not([busy]) .tab-icon-stack {
    width: 0 !important;
    position: absolute;
    bottom: 8px;
  }
}
@mixin pinnedIconHide($prefix: "") {
  #{$prefix} .tab-icon-image {
    display: none !important;
  }
}

.tabbrowser-tab[pinned] {
  @include pinnedCloseButtonShow("&[visuallyselected]:not([style*='transform: translateX']):hover");
  @include pinnedIconStackLayout("&[visuallyselected]:not([style*='transform: translateX']):hover");
  @include pinnedIconHide("&[visuallyselected]:not([style*='transform: translateX']):hover");

  @include Option("userChrome.tab.close_button_at_pinned.always") {
    @include pinnedCloseButtonShow("&[visuallyselected]");
    @include pinnedIconStackLayout("&[visuallyselected]");
    @include pinnedIconHide("&[visuallyselected]");
  }
  @include Option("userChrome.tab.close_button_at_pinned.background") {
    @include pinnedCloseButtonShow("&:not([style*='transform: translateX']):hover");
    @include pinnedIconStackLayout("&:not([style*='transform: translateX']):hover");
    @include pinnedIconHide("&:not([style*='transform: translateX']):hover");
  }
}
#tabbrowser-tabs[closebuttons="activetab"] .tabbrowser-tab[pinned]:not([style*="transform: translateX"]):hover:not([busy]) .tab-close-button {
  margin-inline-end: var(--uc-close-button-margin) !important;
}