tailwindcss

Tailwind CSS Core Knowledge

Deep Knowledge: Use mcp__documentation__fetch_docs with technology: tailwindcss for comprehensive documentation.

Common Utilities

<div class="flex items-center justify-between gap-4"> <div class="grid grid-cols-3 gap-4"> <div class="container mx-auto px-4">

<div class="p-4 m-2 space-y-4"> <div class="px-4 py-2 mt-8 mb-4">

<div class="w-full h-screen max-w-md min-h-[200px]">

<p class="text-lg font-semibold text-gray-900"> <p class="text-sm text-gray-500 leading-relaxed">

<div class="bg-blue-500 text-white border-gray-200"> <div class="bg-gradient-to-r from-blue-500 to-purple-500">

Responsive Design

<div class="text-sm md:text-base lg:text-lg"> <div class="flex-col md:flex-row"> <div class="hidden lg:block">

States

<button class="bg-blue-500 hover:bg-blue-600 active:bg-blue-700"> <input class="border focus:ring-2 focus:ring-blue-500 focus:border-blue-500">

<div class="group"> <span class="group-hover:text-blue-500">Text</span> </div>

<div class="bg-white dark:bg-gray-900 text-gray-900 dark:text-white">

Components Pattern

<div class="rounded-lg shadow-md bg-white p-6 hover:shadow-lg transition-shadow">

<button class="px-4 py-2 rounded-md bg-blue-500 text-white font-medium hover:bg-blue-600 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed">

<input class="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent">

When NOT to Use This Skill

CSS-in-JS preferred - Use styled-components or Emotion
Traditional CSS workflow - Stick with SCSS/PostCSS
Component library projects - Material-UI, Ant Design have their own styling
Email templates - Inline styles required

Config

// tailwind.config.js export default { content: ['./src/**/*.{js,ts,jsx,tsx}'], theme: { extend: { colors: { brand: '#1a73e8' }, fontFamily: { sans: ['Inter', 'sans-serif'] } } }, plugins: [require('@tailwindcss/forms')] }

Anti-Patterns

Anti-Pattern Why It's Bad Correct Approach

Using arbitrary values everywhere Hard to maintain Define in theme config

Long className strings Hard to read Use cn() utility or component extraction

Not using content config Large CSS bundles Specify exact file paths

Inline @apply in HTML Defeats utility-first Use @apply in CSS or extract component

Ignoring purge warnings Unused CSS in production Fix content paths

Not using CSS variables Can't change dynamically Use CSS vars for themeable values

Quick Troubleshooting

Issue Cause Solution

Styles not applying Purge removed classes Add to safelist or fix content paths

Dark mode not working darkMode not set Set darkMode: 'class' in config

Custom colors not working Not in theme.extend Add to theme.extend.colors

Build size too large Including too many files Be specific in content patterns

Hover not working on touch Using :hover only Add focus states for accessibility

Class conflicts Multiple utility classes Use cn() with tailwind-merge

Production Readiness

Performance Optimization

// tailwind.config.js export default { content: [ './src/**/*.{js,ts,jsx,tsx}', // Be specific to avoid scanning node_modules ], theme: { extend: {}, }, // Remove unused utilities in production safelist: [ // Only if dynamically generated { pattern: /bg-(red|green|blue)-(100|500)/ }, ], // Disable unused core plugins corePlugins: { preflight: true, // container: false, // if not using }, };

// postcss.config.js export default { plugins: { 'tailwindcss/nesting': {}, tailwindcss: {}, autoprefixer: {}, // Production only ...(process.env.NODE_ENV === 'production' ? { cssnano: { preset: 'default' } } : {}), }, };

Design System

// tailwind.config.js export default { theme: { // Override defaults colors: { transparent: 'transparent', current: 'currentColor', white: '#ffffff', black: '#000000', // Brand colors primary: { 50: '#eff6ff', 100: '#dbeafe', 500: '#3b82f6', 600: '#2563eb', 700: '#1d4ed8', }, // Semantic colors success: '#22c55e', warning: '#f59e0b', error: '#ef4444', }, // Consistent spacing scale spacing: { px: '1px', 0: '0', 1: '0.25rem', 2: '0.5rem', 3: '0.75rem', 4: '1rem', // ... }, // Typography scale fontSize: { xs: ['0.75rem', { lineHeight: '1rem' }], sm: ['0.875rem', { lineHeight: '1.25rem' }], base: ['1rem', { lineHeight: '1.5rem' }], lg: ['1.125rem', { lineHeight: '1.75rem' }], xl: ['1.25rem', { lineHeight: '1.75rem' }], }, }, };

Component Patterns

// lib/styles.ts - Reusable class compositions import { clsx, type ClassValue } from 'clsx'; import { twMerge } from 'tailwind-merge';

export function cn(...inputs: ClassValue[]) { return twMerge(clsx(inputs)); }

// Variant patterns with cva import { cva, type VariantProps } from 'class-variance-authority';

export const buttonVariants = cva( 'inline-flex items-center justify-center rounded-md font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 disabled:pointer-events-none disabled:opacity-50', { variants: { variant: { default: 'bg-primary-600 text-white hover:bg-primary-700', outline: 'border border-gray-300 hover:bg-gray-50', ghost: 'hover:bg-gray-100', }, size: { sm: 'h-8 px-3 text-sm', md: 'h-10 px-4', lg: 'h-12 px-6 text-lg', }, }, defaultVariants: { variant: 'default', size: 'md', }, } );

Accessibility

<button class="focus:outline-none focus-visible:ring-2 focus-visible:ring-blue-500 focus-visible:ring-offset-2">

<a href="#main" class="sr-only focus:not-sr-only focus:absolute focus:top-4 focus:left-4 focus:z-50 focus:px-4 focus:py-2 focus:bg-white"> Skip to content </a>

<div class="transition-transform motion-reduce:transition-none motion-reduce:transform-none">

<button class="bg-blue-500 forced-colors:bg-[ButtonFace] forced-colors:border forced-colors:border-[ButtonBorder]">

Dark Mode

// tailwind.config.js export default { darkMode: 'class', // or 'media' // ... };

// Theme toggle component function ThemeToggle() { const [theme, setTheme] = useState('light');

useEffect(() => { document.documentElement.classList.toggle('dark', theme === 'dark'); }, [theme]);

return ( <button onClick={() => setTheme(theme === 'light' ? 'dark' : 'light')}> Toggle theme </button> ); }

Testing

// Visual regression testing import { test, expect } from '@playwright/test';

test('button variants render correctly', async ({ page }) => { await page.goto('/storybook/button');

// Screenshot comparison await expect(page.locator('.button-primary')).toHaveScreenshot('button-primary.png'); await expect(page.locator('.button-outline')).toHaveScreenshot('button-outline.png'); });

// Unit testing class compositions import { cn, buttonVariants } from '@/lib/styles';

describe('buttonVariants', () => { it('generates correct classes for default variant', () => { const classes = buttonVariants({ variant: 'default', size: 'md' }); expect(classes).toContain('bg-primary-600'); expect(classes).toContain('h-10'); }); });

Monitoring Metrics

Metric Target

CSS bundle size < 30KB gzipped

Unused CSS 0%

First Contentful Paint < 1s

Lighthouse Performance

90

Checklist

Content paths correctly configured
PostCSS with cssnano in production
Design tokens (colors, spacing, typography)
cn() utility for class merging
CVA for component variants
Dark mode support
Focus-visible for accessibility
Reduced motion support
Bundle size monitoring
Visual regression tests

Reference Documentation

Utilities Cheatsheet
Responsive Patterns

Safety Notice

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Source Transparency

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