DC Lighting
DC powered lighting can be both simple and complicated.
Simple (On/Off)
If you want simple On/Off lights, the solution is simple. Just find LED's that match your the voltage of your lighting circuit and use traditional (non-dimming) light switch.
Complicated (Dimming)
Dimming makes things much more complicated. The dimmer is often tied to a driver (either external or integral to the fixture) and dimmers are predominantly AC to DC converters. It is in theory a simpler circuit, but in practice the finding the parts is much more difficult.
Drivers
Lighting drivers have several functions. Accept line voltage (AC or DC), generate power for a control circuit, and adjust the output voltage.
AC to DC drivers won't work for DC to DC applications. Only certain types of dimmers will work with a DC control circuit.
Dimmers
Types of dimmers include
0-10V (preferred - easiest to trouble shoot)
PWM
EVP dimming
Smart controllers / Wifi
Dimmers are ~90% efficient. 10% is lost in the conversion.
Rumors of a dual mode (AC or DC input) driver
Here is an example of the