Mahoutsukai no Yoru

In the mansion on the hill, there lived two witches... It is the late 1980s—the twilight of an era of beauty and vigor. A boy moves to the city, barely missing two witches living in modern times. The boy leads a completely ordinary life. She carries herself with gallant pride. The girl lives a sleepy, hidden life. Each walks a starlit path. One would never expect their paths to cross. The story of how these three disparate people came together is soon to be told. (From Steam)