Steps into sunken seating area

[MrCarrotHands]

I've ripped out a circular swimming pool that was built into our raised deck (cats started drowning in it...), and needed to replaced it with something- decided on a sunken seating area with firepit (the pool area is 45cm below the lawn level). Going to build wodden seats with steps going up to the deck on one side, and steps opposite those to the lawn (bottom of the circle area). I'm stuck how to build the steps to the lawn though, specifically the sides as don't want earth touching wood. I was thinking of having lights place under each seat with a light in each step, so the lawn step would need to be wood, not concrete etc. Would it be simpler to just have this step to lawn as concrete and forget lighting it? Any advice please? Thanks