Given a .tsx defines a component A() – that has an element <H> , which height property may change. There is a different .tsx having a component B() that includes CSS x.css and this component B() intends to position an element <E> right below the element <H>.

I intend to employ sticky positions for <E> in x.css and calculate the current height of the <H> element something like this:

.e-style {
  position: sticky;
  top: calc(var(--ElementH-height));
}

I would need this to make <E> sticky against scrolling.
Can I set this variable in A()‘s CSS file and if so, will it keep updating ?