We should first consider the definition of light.
ie information carried by photons (electromagnetic waves) in the visible spectrum that our eyes can detect.
The entire spectrum of electromagnetic waves cannot all be defined as light,
so if there is no "light" all we are saying is there are no Electromagnetic waves in that particular part of the spectrum.
So dark according to our definition doesn't imply that there are no other electromagnetic waves, just that we cant detect it with our eyes.
Even the big emptyness is full of energy, which is not visible, but can produce matter. mass equates to energy and vice cersa
