Hokkaido is most known for being like winder wonderland of Japan. And there are many beautiful lighted areas on the darkest seasons of the year as well as Onsens like the Noboribetsu onsen where you can soak and warm up till the late night while enjoying the nature around, walk around the ningle terrace at night for a romantic night. On summer you can walk up to Mt. Hakodate and see the beautiful sight of the close by city lights. Every town has ofcourse some kind of nightlife and bars but Hokkaido is more of a town for a romantic feeling.