The church, while relatively 'antique' in its appearance, is actually dated to the nineteenth century, having been constructed between 1862-1882 -- a sign of a great success, to my mind, that it is so easily confused with a much earlier, Byzantine structure.
Interestingly, the internal mosaics were actually executed by Westerners, specifically artists from Venice (who, of course, would have great exposure to and familiarity with the Italo-Byzantine style that is found in San Marco and other churches within the region of Venezia). The frescoes are the product of a group of Russian, Polish and Ukrainian artists -- with the crown jewel of the cathedral no doubt being the apsidal fresco of the Mother of God, painted by the Russian artist, Viktor Zamyraylo (+1939).
This particular structure is, of course, in many ways very much 'Byzantine' in its inspiration, but what strikes me about it is that, with a few minor tweaks, it could as readily be found in Venice, Ravenna or Rome if we simply tweaked a few of its elements.
A truly stunning structure and example of what yet remains possible in the modern age.