1. CSS overflow: overlay

    The `overlay` value of the `overflow` CSS property is a non-standard value to make scrollbars appear on top of content rather than take up space. This value is deprecated and related functionality being standardized as [the `scrollbar-gutter` property](mdn-css_properties_scrollbar-gutter).

  2. css property: scrollbar-gutter

  3. css property: scrollbar-gutter: auto

  4. css property: scrollbar-gutter: stable