[css-selectors] Proposal for a new nth\last\first\-child selector respecting order

[CyberAP]

It would be nice to have an nth-child selector that respects order of the elements changed with an order property. It could be named like nth-order or nth-by-order.

Usage example:

<div class="container">
  <div class="element first">1</div>
  <div class="element second">2</div>
  <div class="element third">3</div>
</div>

.container
{
  display: flex;
  flex-direction: column;
}
.element.third
{
  order: -1; /* Now it's the first element */
}
.element:not(:nth-last-order)
{
  margin-bottom: 20px; /* Actual last element doesn't have margin */
}

[tabatkins]

Unfortunately, this idea falls into the general category of impossible things that we have to automatically reject: https://wiki.csswg.org/faq#selectors-that-depend-on-layout