Tailwind CSS - Utility Classes

Tailwind CSS is a utility-first CSS framework that provides low-level utility classes to build custom designs without leaving your HTML.

Key Concepts

Utility-First Approach

Instead of writing custom CSS, compose designs using pre-built utility classes:

<!-- Traditional CSS -->
<style>
  .btn {
    background-color: #3b82f6;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 0.25rem;
  }
</style>
<button class="btn">Click me</button>

<!-- Tailwind utility-first -->
<button class="bg-blue-500 text-white px-4 py-2 rounded">
  Click me
</button>

Core Utility Categories

Layout

• Display: block, inline-block, flex, grid, hidden
• Position: static, relative, absolute, fixed, sticky
• Flexbox: flex-row, flex-col, justify-center, items-center, gap-4
• Grid: grid-cols-3, grid-rows-2, col-span-2, row-span-1

Spacing

• Padding: p-4, px-2, py-6, pt-8, pr-3, pb-2, pl-1
• Margin: m-4, mx-auto, my-6, -mt-4 (negative margins)
• Space Between: space-x-4, space-y-2

Typography

• Font Family: font-sans, font-serif, font-mono
• Font Size: text-xs, text-sm, text-base, text-lg, text-xl, text-2xl, text-3xl
• Font Weight: font-thin, font-normal, font-medium, font-semibold, font-bold
• Text Color: text-gray-900, text-blue-500, text-red-600
• Text Alignment: text-left, text-center, text-right, text-justify
• Line Height: leading-none, leading-tight, leading-normal, leading-relaxed

Colors & Backgrounds

• Background Color: bg-white, bg-gray-100, bg-blue-500
• Background Gradient: bg-gradient-to-r from-blue-500 to-purple-600
• Opacity: opacity-0, opacity-50, opacity-100

Borders & Shadows

• Border: border, border-2, border-t, border-gray-300
• Border Radius: rounded, rounded-lg, rounded-full, rounded-none
• Box Shadow: shadow-sm, shadow, shadow-md, shadow-lg, shadow-xl
• Ring: ring-2, ring-blue-500, ring-offset-2

Effects

• Transitions: transition, transition-all, duration-300, ease-in-out
• Transforms: scale-110, rotate-45, translate-x-4, skew-y-3
• Filters: blur-sm, brightness-50, contrast-125, grayscale

Best Practices

1. Responsive Design with Breakpoints

Use responsive prefixes for different screen sizes:

<!-- Mobile-first: stack vertically on small screens, horizontal on medium+ -->
<div class="flex flex-col md:flex-row gap-4">
  <div class="w-full md:w-1/2">Column 1</div>
  <div class="w-full md:w-1/2">Column 2</div>
</div>

<!-- Responsive text sizes -->
<h1 class="text-2xl md:text-4xl lg:text-6xl">
  Responsive Heading
</h1>

Breakpoints:

• sm: - 640px
• md: - 768px
• lg: - 1024px
• xl: - 1280px
• 2xl: - 1536px

2. State Variants

Apply utilities based on state:

<!-- Hover, focus, active states -->
<button class="
  bg-blue-500 hover:bg-blue-700
  text-white
  px-4 py-2 rounded
  transition
  focus:ring-2 focus:ring-blue-300
  active:scale-95
">
  Interactive Button
</button>

<!-- Group hover -->
<div class="group">
  <img class="group-hover:scale-110 transition" src="..." />
  <p class="text-gray-600 group-hover:text-blue-500">
    Hover the parent
  </p>
</div>

3. Dark Mode

Use dark: prefix for dark mode styles:

<div class="
  bg-white dark:bg-gray-800
  text-gray-900 dark:text-white
  border border-gray-200 dark:border-gray-700
">
  Dark mode compatible content
</div>

4. Arbitrary Values

Use square brackets for one-off custom values:

<!-- Custom spacing -->
<div class="mt-[17px] p-[13px]">

<!-- Custom colors -->
<div class="bg-[#1da1f2] text-[rgb(255,100,50)]">

<!-- Custom breakpoints -->
<div class="min-[890px]:flex">

5. Class Organization

Order classes logically for readability:

<!-- Layout → Spacing → Typography → Colors → Effects -->
<div class="
  flex items-center justify-between
  px-6 py-4
  text-lg font-semibold
  bg-white text-gray-900
  shadow-md rounded-lg
  hover:shadow-xl transition
">

Examples

Card Component

<div class="
  max-w-sm mx-auto
  bg-white rounded-lg shadow-md overflow-hidden
  hover:shadow-xl transition-shadow duration-300
">
  <img
    class="w-full h-48 object-cover"
    src="/image.jpg"
    alt="Card image"
  />
  <div class="p-6">
    <h2 class="text-2xl font-bold text-gray-900 mb-2">
      Card Title
    </h2>
    <p class="text-gray-600 leading-relaxed mb-4">
      Card description goes here with some helpful information.
    </p>
    <button class="
      w-full
      bg-blue-500 hover:bg-blue-600
      text-white font-semibold
      py-2 px-4 rounded
      transition-colors
    ">
      Learn More
    </button>
  </div>
</div>

Responsive Navigation

<nav class="
  bg-white shadow-lg
  border-b border-gray-200
">
  <div class="
    max-w-7xl mx-auto
    px-4 sm:px-6 lg:px-8
  ">
    <div class="flex justify-between items-center h-16">
      <!-- Logo -->
      <div class="flex-shrink-0">
        <h1 class="text-2xl font-bold text-blue-600">Logo</h1>
      </div>

      <!-- Desktop Navigation -->
      <div class="hidden md:flex space-x-8">
        <a href="#" class="
          text-gray-700 hover:text-blue-600
          px-3 py-2 rounded-md text-sm font-medium
          transition-colors
        ">
          Home
        </a>
        <a href="#" class="
          text-gray-700 hover:text-blue-600
          px-3 py-2 rounded-md text-sm font-medium
          transition-colors
        ">
          About
        </a>
        <a href="#" class="
          text-gray-700 hover:text-blue-600
          px-3 py-2 rounded-md text-sm font-medium
          transition-colors
        ">
          Contact
        </a>
      </div>

      <!-- Mobile menu button -->
      <div class="md:hidden">
        <button class="
          text-gray-700 hover:text-blue-600
          p-2
        ">
          <svg class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 6h16M4 12h16M4 18h16" />
          </svg>
        </button>
      </div>
    </div>
  </div>
</nav>

Grid Layout

<div class="
  grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3
  gap-6
  p-6
">
  <div class="bg-white p-6 rounded-lg shadow">Item 1</div>
  <div class="bg-white p-6 rounded-lg shadow">Item 2</div>
  <div class="bg-white p-6 rounded-lg shadow">Item 3</div>
  <div class="bg-white p-6 rounded-lg shadow col-span-1 md:col-span-2">
    Wide Item
  </div>
  <div class="bg-white p-6 rounded-lg shadow">Item 5</div>
</div>

Common Patterns

Centering Content

<!-- Flexbox centering -->
<div class="flex items-center justify-center min-h-screen">
  <div>Centered content</div>
</div>

<!-- Grid centering -->
<div class="grid place-items-center min-h-screen">
  <div>Centered content</div>
</div>

<!-- Absolute centering -->
<div class="relative h-screen">
  <div class="absolute top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2">
    Centered content
  </div>
</div>

Truncating Text

<!-- Single line truncate -->
<p class="truncate">
  This text will be truncated with an ellipsis if it's too long
</p>

<!-- Multi-line truncate -->
<p class="line-clamp-3">
  This text will be truncated after 3 lines with an ellipsis
</p>

Aspect Ratios

<!-- 16:9 aspect ratio -->
<div class="aspect-video bg-gray-200">
  <iframe src="..." class="w-full h-full"></iframe>
</div>

<!-- Square aspect ratio -->
<div class="aspect-square bg-gray-200">
  <img src="..." class="w-full h-full object-cover" />
</div>

Anti-Patterns

❌ Don't Use Inline Styles

<!-- Bad: Mixing inline styles with Tailwind -->
<div class="p-4" style="margin-top: 20px;">
  Content
</div>

<!-- Good: Use Tailwind utilities -->
<div class="p-4 mt-5">
  Content
</div>

❌ Don't Create Unnecessary Wrapper Divs

<!-- Bad: Extra wrapper for centering -->
<div class="flex justify-center">
  <div class="text-center">
    <h1>Title</h1>
  </div>
</div>

<!-- Good: Direct styling -->
<h1 class="text-center">Title</h1>

❌ Don't Overuse Arbitrary Values

<!-- Bad: Too many custom values -->
<div class="mt-[17px] mb-[23px] pt-[11px] pb-[19px]">

<!-- Good: Use standard spacing scale -->
<div class="my-6 py-3">

❌ Don't Forget Mobile-First

<!-- Bad: Desktop-first approach -->
<div class="w-1/2 sm:w-full">

<!-- Good: Mobile-first approach -->
<div class="w-full sm:w-1/2">

Related Skills

• tailwind-configuration: Customizing Tailwind config and theme
• tailwind-components: Building reusable component patterns
• tailwind-responsive-design: Advanced responsive design techniques
• tailwind-performance: Optimizing Tailwind for production