Comment by Hahahaha_lol on Hotaru no Yomeiri - Chapter 18

Notice how her eyes are black when taking care of him - she's becoming pessimistic! Yet those eyes which also belong to Shinpei, as previously pointed out by Shinpei himself, are dark and gloomy. In contrast to her own bright eyes (eyes that represent her hope to leave the island and fulfill her duty), he has not much hope for the future. Yet when Shinpei is injured, her formerly bright eyes turn dark. This signifies the physical representation of her gaining new goals - such as Shinpei being safe. She now cares about him. The darkening shows that the goal was not protected, and she felt hopeless. She has...fallen in love, indeed.