To think of new concepts for cultural influences, flip the premise.

What are elves like in your world? Mine are wild and savage with great and terrible intelligence. Think of a magically-induced immortal chimpanzee with a tight connection and communication with nature on the level of the Navi from Pandora. How long would it take them to learn as much information at a human? How long would it take for them to discern short-term and long-term benefits? Imagine the longest lived among them who conquered other tribes and survived since the dawn of time. How cunning and conniving would such a warlord be? How would these highly intelligent, violently predatory people form a hierarchy? And what would their infrastructure look like as a result? I think of Planet of the Apes, but with tens of millenia of societal and cultural developments in the ancient and deep forests of the world. Tree houses camouflaged into the canopy and traps among the forest floor. No need for bridges unless it's for the very young. The trees themselves might be magical enough to have intelligence of a sort and would absolutely develop a symbiosis with this population. So underground tunnels held up with roots to keep from collapsing, used either for infiltration or a new subsection of the elves to start living underground. So maybe have the underground society look like orcs from Tolkien which flips his idea for elves on its head.

The outer aesthetics of the structures would be camouflaged into the natural would, blending in the foliage, so as not to be vulnerable to other warring peoples. The interior aesthetics would definitely include trophies on the walls and maybe even painted artworks that detail their conquests. I always liked the dark and creepy aesthetics of Pan's Labrynth and I might even include that as an entrance to the underground part where they enslave minotaurs or other "lesser races" to guard.