What are CSS-in-JS libraries?

Short answer: CSS-in-JS libraries allow you to write CSS styles directly inside JavaScript files, enabling better component encapsulation and dynamic styling. Popular libraries include:

Real-world example (ShopNest)

ShopNest’s storefront is React: components for ProductCard, CartDrawer, and CheckoutForm, with hooks for local UI state.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.