Hello! First I looooooooooove your art like I really do! Second: What do Paprika's eyes look like? I'm thinking about cosplaying her so, that is an important question! :p
They’re most commonly all black, but for Art-Reasons I usually just make them whatever colour is darkest in the picture (same goes for her hair). Whether they’re deep voids or just really big pupils is up for debate.
Black sclera lenses would be the most accurate, but they’re really expensive and can’t be worn very long. I see a lot of people just photoshop their eyes when it’s stuff like this.