The new site is actually a re-opening of the old darksouls.jp domain, now themed after the new game.
Interestingly, while the game was showcased at Microsoft’s press conference at E3, the pictures of the boxes on the website showcase the PS4 version on the front, which normally identifies Sony as the primary marketing partner.
Considering that this specific site is aimed to the Japanese market, though, this could be limited to Japan only, where the PS4 is the dominant current generation console. In the official press materials distributed for the west after E3, the boxes are portrayed separate (you can see both versions below).
It’ll be interesting to see what cover will end up in the front when the western website will be updated.