tailwind-merge : Deterministic Class Override

tailwind-merge is a runtime library that takes any number of Tailwind class strings and returns ONE string where conflicting utilities are resolved with a LAST-WINS rule.

It is the foundation of the shadcn/ui cn() helper, the cva-based component variant pattern, and any React/Vue/Svelte component that accepts a className prop and combines it with internal defaults.

Companion skills :

• tailwind-impl-config-v3 and tailwind-impl-config-v4 : the Tailwind side of the equation.
• tailwind-impl-plugins-official : how the official plugins emit class groups that tailwind-merge needs to know about.
• shadcn-ui skill package : the upstream design system that popularised the cn helper.