Advice on water base and land transition

Hi all,

Looking for advice on something I’m having trouble finding an answer to.

I have an 18x18x24 exo terra tank and I’m making my first paludarium. It’s 4.5” deep before the seem and I intend to have the first 4” of base length be water then transition to land. I’m using egg crate and screen mesh (maybe foam as well).

I’m doing a jungle theme (think Costa Rica) and would like to add dart frogs eventually.
I’m having trouble understanding what ‘base’ should be used for the water and how to transition it to land visually.

I’ve seen recommendations for pebbles, sand, and aqua sand/aqua scape. I’ve also seen recs to leave it blank.

What would be best and how do I ‘visually’ create transition to land - is it through use of hardscape like dragonstone and tissue paper? Other alternatives?

For hardscape I’m thinking manzanita and spider wood and perhaps some slate - again in line with the jungle theme. Thanks advance :)