Attracive Deck Lighting/Outlets How?

Preparing to run lighting and outlets to an expansive and lovely deck under construction. I planned to use THWN/THNN in conduit attached to the bottom of the deck, but how can I make it look good, i.e. avoid exposed conduit above the deck surface? There will be receptacles as well as BOTH 12V LV lighting and a couple 110V lights on tall posts.

I have heard of using the posts as raceways for wiring, but can this be done to code, and how would you transition from conduit to the posts?

The deck is composite (trex) and the posts will either be trex (hollow center) OR specialty surface mount steel core posts with vinyl casing that go with vinyls rail system, OR 4x4 with vinyl casing. The type of post chosen will depend on the wiring options available.

Ideas? Must be code compliant.