[Bug]: overflow: overlay is a legacy value

[sebastianthulin]

Expected Behavior

This is a validation error; I'm expecting that the css fully validates.

Current Behavior

The CSS does not validate; but it still works.

Steps to reproduce

W3C validation.

Proposed fix or additional info.

Replace the overflow: overlay; legacy fix with the scrollbar-gutter property in CSS ML4. The property has good coverage according to can i use: https://caniuse.com/mdn-css_properties_scrollbar-gutter

Version

On which browser do you see the issue?

No response