Component · fallback
The comparison is shown, stopped where --cs-position puts
it — here at 38 %, set in the stylesheet of this page. Both images
are loaded, both labels are readable, the seam is in the right
place : nothing is broken, nothing is hidden.
The slider, on the other hand, is removed. There is no way at all to
tie an <input type="range"> to a custom property
without a script ; leaving in place a control that moves without
moving anything would be a lie, and it would have had to be made
focusable in order to lead nowhere. So it goes, rather than pretend.
--cs-position