Kitty and Kostya are both what kind of character type, and to which effect?

Kitty and Kostya are both characters with contrasting personality types. Kitty is described as a sociable, graceful, and charming character, while Kostya is introverted, brooding, and melancholic. This contrast between the two characters serves to highlight their differing perspectives on life, love, and society. Kitty's outgoing nature and positive outlook on life provide a foil to Kostya's internal struggles and negative view of the world, creating a dynamic that adds depth to the story and encourages the reader to consider the complexities of human nature.