I've learnt CSS like below statement:
It only can go further or deeper in
DOM.
And that's the reason we don't have a previous selector like we do for next selector ( selector + nextLM ) or we don't have a parent selector because we can't go backwards in DOM tree as CSS engine's point of view.
So there should be two different questions here. If we accept the above explanation, I can't understand how can :nth-last-child() work. It's basically going backwards in DOM tree as it starts at the end of an element.
And if we don't accept our introduction, then why don't we have a previous element selector?
Thanks in advance for your time.