I have seen a few stories with a similar premise come out recently, (The Invisible Man and His Soon-to-Be Wife), but overall, I haven't seen this idea before. At least not in this setting. There such a cute couple and I'm defiantly routing for them. The art style is fitting for the story, and the art on the cover is the art for the entire manga. The story focuses almost entirely on the two main characters, and they feel relatively fleshed out for how short the story is. Your main issue will be finding the rest of the chapters, if you do let me know!