revert commit 1fe19578c2 which changed `anchor()` values to `position-area`.
I'm not sure what compelled me to do that change initially, except the easier to understand syntax. Hopefully it wasn't important.
But oddbird polyfill expects `anchor()` values, which it converts to pixel values for positioning.
This updates the position try results by using a different method of setting the area of the anchored element. Rather than using the inset properties with `anchor()`, it uses `position-area`.