Defensive CSS is a Stylelint plugin that enforces best practices for writing resilient, accessible CSS. It provides 14 rules covering accessibility (like requiring focus-visible and prefers-reduced-motion), layout stability (preventing fixed sizes and scroll chaining), and performance (avoiding unsafe will-change usage). The plugin is designed for front-end developers and teams who want to catch common CSS anti-patterns early in development, with preset configurations for recommended, accessibility-focused, or strict linting setups.