UnoCSS is an instant atomic CSS engine designed to be flexible and extensible. The core is un-opinionated - all CSS utilities are provided via presets. It's a superset of Tailwind CSS, so you can reuse your Tailwind knowledge for basic syntax usage.

Important: Before writing UnoCSS code, agents should check for uno.config.* or unocss.config.* files in the project root to understand what presets, rules, and shortcuts are available. If the project setup is unclear, avoid using attributify mode and other advanced features - stick to basic class usage.

The skill is based on UnoCSS 66.x, generated at 2026-01-28.

Core

Presets

Main Presets

Feature Presets

Transformers

Integrations

Nuxt 4+ Development

Progressive guidance for Nuxt 4+ projects (v4.3+) with latest patterns and conventions.

When to Use

Working with:

• Server routes (API endpoints, server middleware, server utils)
• File-based routing (pages, layouts, route groups)
• Nuxt middleware (route guards, navigation)
• Nuxt plugins (app extensions)
• Nuxt-specific features (auto-imports, layers, modules)

Available Guidance

Read specific files based on current work:

• references/server.md - API routes, server middleware, validation (Zod), WebSocket, SSE
• references/routing.md - File-based routing, route groups, typed router, definePage
• references/middleware-plugins.md - Route middleware, plugins, app lifecycle
• references/nuxt-composables.md - Nuxt composables (useRequestURL, useFetch, navigation)
• references/nuxt-components.md - NuxtLink, NuxtImg, NuxtTime (prefer over HTML elements)
• references/nuxt-config.md - Configuration, modules, auto-imports, layers

For Vue composables: See vue skill composables.md (VueUse, Composition API patterns) For UI components: use nuxt-ui skill For database/storage: use nuxthub skill For content-driven sites: use nuxt-content skill For creating modules: use nuxt-modules skill For project scaffolding/CI: use ts-library skill

Loading Files

Consider loading these reference files based on your task:

• references/server.md - if creating API endpoints or server middleware
• references/routing.md - if setting up pages, layouts, or route groups
• references/nuxt-composables.md - if using Nuxt composables (useFetch, useRequestURL, etc.)
• references/middleware-plugins.md - if working with middleware or plugins
• references/nuxt-components.md - if using Nuxt components (NuxtLink, NuxtImg, etc.)
• references/nuxt-config.md - if editing nuxt.config.ts
• references/project-setup.md - if setting up CI/ESLint/build tools

DO NOT load all files at once. Load only what's relevant to your current task.

Quick Start

// server/api/hello.get.ts
import { z } from "zod";

export default defineEventHandler(async (event) => {
    const { name } = await getValidatedQuery(
        event,
        z.object({
            name: z.string().default("world"),
        }).parse,
    );
    return { message: `Hello ${name}` };
});

Nuxt 4 vs Older Versions

You are working with Nuxt 4+. Key differences:

If you're unsure about Nuxt 4 patterns, read the relevant guidance file first.

Latest Documentation

When to fetch latest docs:

• New Nuxt 4 features not covered here
• Module-specific configuration
• Breaking changes or deprecations
• Advanced use cases

Official sources:

• Nuxt: https://nuxt.com/docs
• h3 (server engine): https://v1.h3.dev/
• Nitro: https://nitro.build/

Token Efficiency

Main skill: ~300 tokens. Each sub-file: ~800-1500 tokens. Only load files relevant to current task.