message: Tabs: fixed z-index for FixedLayout vertical="bottom"
diff: background: var(--background_content);
  }
  - .FixedLayout--ios.FixedLayout--bottom .TabsItem,
  + .FixedLayout--ios.FixedLayout--bottom .Tabs__in,
  .FixedLayout--ios.FixedLayout--bottom .Separator {
  position: relative;
  z-index: 2;
  