Mobile-First Responsive Design (2025/2026)

Core Philosophy

Mobile-first design is the industry standard for 2025/2026. With mobile traffic consistently exceeding 60% of global web traffic and Google's mobile-first indexing, starting with mobile ensures optimal user experience and SEO performance.

The Mobile-First Mindset

<!-- CORRECT: Mobile-first (progressive enhancement) --> <div class="text-sm md:text-base lg:text-lg"> Start small, enhance upward </div>

<!-- INCORRECT: Desktop-first (graceful degradation) --> <div class="lg:text-lg md:text-base text-sm"> Starts large, reduces down (more code, more bugs) </div>

Key Principle: Unprefixed utilities apply to ALL screen sizes. Breakpoint prefixes apply at that size AND ABOVE.

2025/2026 Breakpoint Strategy

Tailwind's Default Breakpoints

Prefix Min-width Target Devices

(none) 0px All mobile phones (base)

sm:

640px (40rem) Large phones, small tablets

md:

768px (48rem) Tablets (portrait)

lg:

1024px (64rem) Tablets (landscape), laptops

xl:

1280px (80rem) Desktops

2xl:

1536px (96rem) Large desktops

Content-Driven Breakpoints

Best Practice 2025/2026: Let content determine breakpoints, not device dimensions.

@theme { /* Override defaults based on YOUR content needs / --breakpoint-sm: 36rem; / 576px - when your content needs more space / --breakpoint-md: 48rem; / 768px / --breakpoint-lg: 62rem; / 992px - common content width / --breakpoint-xl: 75rem; / 1200px / --breakpoint-2xl: 90rem; / 1440px */

/* Add custom breakpoints for specific content needs / --breakpoint-xs: 20rem; / 320px - very small devices / --breakpoint-3xl: 120rem; / 1920px - ultra-wide */ }

Screen Coverage Strategy

<!-- Cover the most common device ranges (2025/2026 data) -->

<!-- 375px-430px: ~50% of mobile devices (iPhone, modern Android) --> <div class="px-4">Mobile base</div>

<!-- 768px+: Tablets and small laptops --> <div class="px-4 md:px-6">Tablet enhancement</div>

<!-- 1024px+: Desktop experience --> <div class="px-4 md:px-6 lg:px-8">Desktop enhancement</div>

<!-- 1440px+: Wide desktop experience --> <div class="px-4 md:px-6 lg:px-8 xl:px-12">Wide desktop</div>

Fluid Typography System

CSS Clamp for Smooth Scaling

Fluid typography eliminates jarring size jumps between breakpoints:

@theme { /* Fluid typography scale */ --text-fluid-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem); --text-fluid-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem); --text-fluid-base: clamp(1rem, 0.9rem + 0.5vw, 1.125rem); --text-fluid-lg: clamp(1.125rem, 1rem + 0.625vw, 1.25rem); --text-fluid-xl: clamp(1.25rem, 1rem + 1.25vw, 1.5rem); --text-fluid-2xl: clamp(1.5rem, 1.1rem + 2vw, 2rem); --text-fluid-3xl: clamp(1.875rem, 1.2rem + 3.375vw, 2.5rem); --text-fluid-4xl: clamp(2.25rem, 1rem + 6.25vw, 3.5rem); --text-fluid-5xl: clamp(3rem, 1rem + 10vw, 5rem); }

Important for Accessibility: Always combine vw with rem to respect user zoom preferences (WCAG compliance).

Using Fluid Typography

<!-- Fluid heading that scales smoothly --> <h1 class="text-fluid-4xl font-bold leading-tight"> Responsive Heading </h1>

<!-- Fluid body text --> <p class="text-fluid-base leading-relaxed max-w-prose"> Body text that scales proportionally with the viewport while respecting user's font size preferences. </p>

<!-- Fluid with breakpoint overrides for fine control --> <h2 class="text-fluid-2xl lg:text-fluid-3xl font-semibold"> Section Title </h2>

Fluid Spacing System

Clamp-Based Spacing

@theme { /* Fluid spacing scale */ --spacing-fluid-xs: clamp(0.25rem, 0.2rem + 0.25vw, 0.5rem); --spacing-fluid-sm: clamp(0.5rem, 0.4rem + 0.5vw, 1rem); --spacing-fluid-md: clamp(1rem, 0.75rem + 1.25vw, 2rem); --spacing-fluid-lg: clamp(1.5rem, 1rem + 2.5vw, 3rem); --spacing-fluid-xl: clamp(2rem, 1.25rem + 3.75vw, 4rem); --spacing-fluid-2xl: clamp(3rem, 1.5rem + 7.5vw, 6rem); --spacing-fluid-section: clamp(4rem, 2rem + 10vw, 8rem); }

Using Fluid Spacing

<!-- Fluid section padding --> <section class="py-fluid-section px-fluid-md"> <div class="max-w-7xl mx-auto"> <h2 class="mb-fluid-lg">Section Title</h2> <div class="grid gap-fluid-md grid-cols-1 md:grid-cols-2 lg:grid-cols-3"> <!-- Cards --> </div> </div> </section>

<!-- Hero section with fluid spacing --> <header class="min-h-screen flex items-center py-fluid-2xl px-fluid-md"> <div class="max-w-4xl"> <h1 class="text-fluid-5xl mb-fluid-md">Hero Title</h1> <p class="text-fluid-lg mb-fluid-lg">Hero description</p> <button class="px-fluid-md py-fluid-sm">Get Started</button> </div> </header>

Touch-Friendly Interactive Elements

WCAG 2.2 Touch Target Requirements

Minimum sizes (2025 standards):

• WCAG 2.2 Level AA: 24x24 CSS pixels minimum

• Recommended: 44x44 CSS pixels (Apple, Google, Microsoft guidelines)

• Optimal: 48x48 CSS pixels for critical actions

<!-- WCAG 2.2 compliant touch targets -->

<!-- Minimum AA compliant (24px) --> <button class="min-h-6 min-w-6 p-1"> <svg class="h-4 w-4">...</svg> </button>

<!-- Recommended size (44px) --> <button class="min-h-11 min-w-11 p-2.5"> <svg class="h-6 w-6">...</svg> <span class="sr-only">Action</span> </button>

<!-- Optimal for primary actions (48px) --> <button class="min-h-12 min-w-12 px-6 py-3 text-base"> Primary Action </button>

Extended Touch Targets

<!-- Extend touch target beyond visible element --> <a href="/link" class="relative inline-block text-sm"> Small visible link <!-- Invisible extended touch area --> <span class="absolute -inset-3" aria-hidden="true"></span> </a>

<!-- Icon button with extended target --> <button class="relative p-2 -m-2 rounded-lg hover:bg-gray-100"> <svg class="h-5 w-5" aria-hidden="true">...</svg> <span class="sr-only">Close</span> </button>

Touch Target Spacing

<!-- Adequate spacing between touch targets (minimum 8px gap) --> <nav class="flex gap-3"> <a href="#" class="min-h-11 px-4 py-2.5">Home</a> <a href="#" class="min-h-11 px-4 py-2.5">About</a> <a href="#" class="min-h-11 px-4 py-2.5">Contact</a> </nav>

<!-- Stacked navigation with adequate spacing --> <nav class="flex flex-col"> <a href="#" class="py-3 px-4 min-h-11 border-b border-gray-100">Link 1</a> <a href="#" class="py-3 px-4 min-h-11 border-b border-gray-100">Link 2</a> <a href="#" class="py-3 px-4 min-h-11">Link 3</a> </nav>

<!-- Button group with safe spacing --> <div class="flex flex-wrap gap-3"> <button class="min-h-11 px-4 py-2">Cancel</button> <button class="min-h-11 px-4 py-2 bg-blue-600 text-white">Confirm</button> </div>

Container Queries (2025 Game-Changer)

Container queries enable component-level responsiveness, independent of viewport size.

Setup

@import "tailwindcss"; @plugin "@tailwindcss/container-queries";

Container Query Breakpoints

Class Min-width

@xs

20rem (320px)

@sm

24rem (384px)

@md

28rem (448px)

@lg

32rem (512px)

@xl

36rem (576px)

@2xl

42rem (672px)

@3xl

48rem (768px)

@4xl

56rem (896px)

@5xl

64rem (1024px)

Practical Container Query Patterns

<!-- Card that responds to its container, not viewport --> <article class="@container"> <div class=" flex flex-col @sm:flex-row gap-4 p-4 bg-white rounded-xl shadow-sm "> <img src="..." class=" w-full @sm:w-32 @lg:w-48 aspect-video @sm:aspect-square object-cover rounded-lg " /> <div class="flex-1 min-w-0"> <h3 class="text-base @md:text-lg @lg:text-xl font-semibold truncate"> Card Title </h3> <p class=" text-sm @md:text-base text-gray-600 line-clamp-2 @lg:line-clamp-3 mt-2 "> Description that adapts to available space... </p> <div class="mt-4 flex flex-wrap gap-2 @md:gap-3"> <span class="text-xs @md:text-sm px-2 py-1 bg-gray-100 rounded">Tag</span> </div> </div> </div> </article>

Named Containers

<div class="@container/sidebar w-64"> <nav class=" flex flex-col @lg/sidebar:flex-row @lg/sidebar:items-center gap-2 @lg/sidebar:gap-4 "> <a href="#">Link 1</a> <a href="#">Link 2</a> </nav> </div>

<main class="@container/main flex-1"> <div class=" grid grid-cols-1 @md/main:grid-cols-2 @xl/main:grid-cols-3 gap-6 "> <!-- Grid items respond to main container --> </div> </main>

When to Use Container vs Viewport Queries

Use Container Queries Use Viewport Queries

Reusable components Page-level layouts

Sidebar widgets Navigation bars

Card grids Hero sections

Embedded content Full-width sections

CMS/dynamic content Fixed app shells

Responsive Layout Patterns

Mobile-First Grid System

<!-- Auto-responsive grid with minimum card width --> <div class=" grid gap-6 grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 "> <!-- Cards automatically flow --> </div>

<!-- CSS Grid auto-fit (no breakpoints needed) --> <div class="grid grid-cols-[repeat(auto-fit,minmax(280px,1fr))] gap-6"> <!-- Cards auto-fit with 280px minimum --> </div>

<!-- CSS Grid auto-fill for fixed-size items --> <div class="grid grid-cols-[repeat(auto-fill,minmax(200px,1fr))] gap-4"> <!-- Fixed minimum size, grows to fill --> </div>

Responsive Flexbox Patterns

<!-- Stack to row --> <div class="flex flex-col md:flex-row gap-4"> <div class="flex-1">Content 1</div> <div class="flex-1">Content 2</div> </div>

<!-- Wrap with centered items --> <div class="flex flex-wrap justify-center gap-4"> <div class="w-full sm:w-auto">Item 1</div> <div class="w-full sm:w-auto">Item 2</div> <div class="w-full sm:w-auto">Item 3</div> </div>

<!-- Mobile stack, desktop inline with push --> <div class="flex flex-col sm:flex-row sm:items-center gap-4"> <div class="flex-1"> <h3>Title</h3> <p class="text-sm text-gray-600">Description</p> </div> <button class="sm:ml-auto min-h-11 px-4 py-2">Action</button> </div>

Responsive Sidebar Layouts

<!-- Collapsible sidebar --> <div class="flex min-h-screen"> <!-- Sidebar: hidden on mobile, visible on desktop --> <aside class=" hidden lg:flex lg:flex-col w-64 border-r bg-gray-50 "> <nav class="flex-1 p-4">...</nav> </aside>

<!-- Main content --> <main class="flex-1 p-4 lg:p-8"> Content </main> </div>

<!-- Mobile drawer + desktop sidebar --> <div class="relative flex min-h-screen"> <!-- Mobile drawer overlay --> <div class=" fixed inset-0 z-40 lg:hidden bg-black/50 data-[open=false]:hidden " data-open="false"> <aside class="w-64 h-full bg-white"> Mobile navigation </aside> </div>

<!-- Desktop sidebar --> <aside class="hidden lg:block w-64 border-r"> Desktop navigation </aside>

<main class="flex-1">Content</main> </div>

Holy Grail Layout (2025)

<div class="min-h-screen grid grid-rows-[auto_1fr_auto]"> <!-- Header --> <header class="sticky top-0 z-50 h-16 bg-white border-b shadow-sm"> <nav class="h-full max-w-7xl mx-auto px-4 flex items-center justify-between"> <Logo /> <ul class="hidden md:flex gap-6">...</ul> <button class="md:hidden min-h-11 min-w-11">Menu</button> </nav> </header>

<!-- Main content area with optional sidebars --> <div class=" grid grid-cols-1 md:grid-cols-[240px_1fr] lg:grid-cols-[240px_1fr_280px] gap-0 "> <nav class="hidden md:block border-r p-4">Left Nav</nav> <main class="p-4 md:p-6 lg:p-8">Main Content</main> <aside class="hidden lg:block border-l p-4">Right Sidebar</aside> </div>

<!-- Footer --> <footer class="bg-gray-900 text-white py-8 md:py-12"> Footer content </footer> </div>

Responsive Images

Aspect Ratio Containers

<!-- Maintain aspect ratio across all sizes --> <div class="aspect-video overflow-hidden rounded-lg"> <img src="..." class="w-full h-full object-cover" loading="lazy" /> </div>

<!-- Responsive aspect ratio --> <div class="aspect-square sm:aspect-video lg:aspect-[4/3] overflow-hidden"> <img src="..." class="w-full h-full object-cover" /> </div>

Responsive Image Sizes

<!-- Art direction with picture element --> <picture> <source media="(min-width: 1024px)" srcset="large.jpg" /> <source media="(min-width: 640px)" srcset="medium.jpg" /> <img src="small.jpg" alt="Description" class="w-full h-auto rounded-lg" loading="lazy" /> </picture>

<!-- Responsive srcset --> <img src="image-800.jpg" srcset=" image-400.jpg 400w, image-800.jpg 800w, image-1200.jpg 1200w, image-1600.jpg 1600w " sizes=" (min-width: 1280px) 1200px, (min-width: 768px) 80vw, 100vw " alt="Responsive image" class="w-full h-auto" loading="lazy" />

Responsive Typography Patterns

Heading Hierarchy

<!-- Mobile-first heading scale --> <h1 class=" text-2xl sm:text-3xl md:text-4xl lg:text-5xl xl:text-6xl font-bold leading-tight tracking-tight "> Main Heading </h1>

<h2 class=" text-xl sm:text-2xl md:text-3xl lg:text-4xl font-semibold leading-snug "> Section Heading </h2>

<h3 class=" text-lg sm:text-xl md:text-2xl font-medium "> Subsection Heading </h3>

Readable Body Text

<!-- Optimal line length and spacing --> <article class="max-w-prose mx-auto"> <p class=" text-base md:text-lg leading-relaxed md:leading-loose text-gray-700 dark:text-gray-300 "> Body text optimized for readability with 45-75 characters per line. </p> </article>

<!-- Text that balances across lines --> <h2 class="text-balance text-2xl md:text-3xl font-bold max-w-2xl"> This heading will balance text across lines to avoid orphans </h2>

Mobile Navigation Patterns

Hamburger to Full Nav

<nav class="relative"> <!-- Desktop navigation --> <ul class="hidden md:flex items-center gap-6"> <li><a href="#" class="py-2 hover:text-blue-600">Home</a></li> <li><a href="#" class="py-2 hover:text-blue-600">Products</a></li> <li><a href="#" class="py-2 hover:text-blue-600">About</a></li> <li><a href="#" class="py-2 hover:text-blue-600">Contact</a></li> </ul>

<!-- Mobile menu button --> <button class="md:hidden min-h-11 min-w-11 p-2" aria-expanded="false" aria-controls="mobile-menu" aria-label="Toggle navigation menu"

<svg class="h-6 w-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">

  <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 6h16M4 12h16M4 18h16"/>
</svg>

</button>

<!-- Mobile menu (controlled via JS) --> <div id="mobile-menu" class=" md:hidden absolute top-full left-0 right-0 bg-white shadow-lg border-t hidden "

<ul class="py-2">

  <li><a href="#" class="block px-4 py-3 min-h-11 hover:bg-gray-50">Home</a></li>
  <li><a href="#" class="block px-4 py-3 min-h-11 hover:bg-gray-50">Products</a></li>
  <li><a href="#" class="block px-4 py-3 min-h-11 hover:bg-gray-50">About</a></li>
  <li><a href="#" class="block px-4 py-3 min-h-11 hover:bg-gray-50">Contact</a></li>
</ul>

</div> </nav>

Bottom Navigation (Mobile App Style)

<!-- Fixed bottom navigation for mobile --> <nav class=" fixed bottom-0 inset-x-0 z-50 md:hidden bg-white border-t shadow-lg safe-area-pb "> <ul class="flex justify-around"> <li> <a href="#" class=" flex flex-col items-center min-h-14 min-w-14 px-3 py-2 text-xs text-gray-600 hover:text-blue-600 aria-current:text-blue-600 "> <svg class="h-6 w-6 mb-1">...</svg> Home </a> </li> <li> <a href="#" class="flex flex-col items-center min-h-14 min-w-14 px-3 py-2 text-xs"> <svg class="h-6 w-6 mb-1">...</svg> Search </a> </li> <li> <a href="#" class="flex flex-col items-center min-h-14 min-w-14 px-3 py-2 text-xs"> <svg class="h-6 w-6 mb-1">...</svg> Profile </a> </li> </ul> </nav>

<!-- Add padding to main content to prevent overlap --> <main class="pb-20 md:pb-0"> Content </main>

Safe Area Handling (Notched Devices)

@utility safe-area-pt { padding-top: env(safe-area-inset-top); }

@utility safe-area-pb { padding-bottom: env(safe-area-inset-bottom); }

@utility safe-area-pl { padding-left: env(safe-area-inset-left); }

@utility safe-area-pr { padding-right: env(safe-area-inset-right); }

@utility safe-area-p { padding-top: env(safe-area-inset-top); padding-right: env(safe-area-inset-right); padding-bottom: env(safe-area-inset-bottom); padding-left: env(safe-area-inset-left); }

<!-- Header that respects notch --> <header class="sticky top-0 safe-area-pt bg-white"> <div class="h-16 flex items-center px-4"> Navigation </div> </header>

<!-- Bottom navigation with safe area --> <nav class="fixed bottom-0 inset-x-0 safe-area-pb bg-white border-t"> Bottom nav </nav>

Performance Optimization for Mobile

Lazy Loading

<!-- Native lazy loading for images --> <img src="image.jpg" alt="..." loading="lazy" class="w-full h-auto" />

<!-- Lazy load below-fold content --> <div class="contents" data-lazy-load> Heavy component loaded on demand </div>

Content Visibility

@utility content-auto { content-visibility: auto; contain-intrinsic-size: auto 500px; }

<!-- Skip rendering off-screen content --> <section class="content-auto"> Large section that may be off-screen </section>

Reduced Data Usage

<!-- Show simpler version on slow connections --> <picture> <source srcset="video-poster.jpg" media="(prefers-reduced-data: reduce)" /> <img src="animated.gif" alt="..." /> </picture>

Responsive Testing Checklist

Essential Tests

• 320px - Smallest supported width (older iPhones)

• 375px - Modern iPhone base

• 414px - Large phones (iPhone Plus/Max)

• 768px - iPad portrait

• 1024px - iPad landscape / small laptop

• 1280px - Standard laptop

• 1440px - Large desktop

• 1920px - Full HD desktop

Quality Checks

• Text remains readable at all sizes

• Touch targets are minimum 44px on mobile

• No horizontal scroll on any viewport

• Images don't overflow containers

• Navigation is accessible on all sizes

• Forms are usable on mobile

• Modals fit mobile screens

• Tables have mobile alternatives

• Performance under 3s LCP on 3G

Responsive Video Containers

Aspect Ratio Utilities for Video

Use Tailwind's aspect-* utilities to maintain correct video proportions across all screen sizes, preventing Cumulative Layout Shift (CLS):

<!-- Standard 16:9 video container --> <div class="aspect-video overflow-hidden rounded-lg bg-black"> <video class="w-full h-full object-cover" playsinline preload="metadata"> <source src="video.mp4" type="video/mp4" /> </video> </div>

<!-- Vertical video (9:16) for mobile-first social content --> <div class="aspect-[9/16] overflow-hidden rounded-lg bg-black max-w-sm mx-auto"> <video class="w-full h-full object-cover" playsinline muted loop> <source src="reel.mp4" type="video/mp4" /> </video> </div>

<!-- Square video (1:1) common for social feeds --> <div class="aspect-square overflow-hidden rounded-lg bg-black"> <video class="w-full h-full object-cover" playsinline preload="metadata"> <source src="square.mp4" type="video/mp4" /> </video> </div>

<!-- Responsive aspect ratio - vertical on mobile, widescreen on desktop --> <div class="aspect-[9/16] sm:aspect-video overflow-hidden rounded-lg bg-black"> <video class="w-full h-full object-contain" playsinline preload="metadata"> <source src="video.mp4" type="video/mp4" /> </video> </div>

Preventing CLS with Video Placeholders

Videos without defined dimensions cause layout shift when they load. Use aspect ratio containers to reserve space:

<!-- CLS-safe video with poster and skeleton loader --> <div class="relative aspect-video overflow-hidden rounded-lg bg-gray-900"> <!-- Skeleton placeholder while video loads --> <div class="absolute inset-0 animate-pulse bg-gray-800" aria-hidden="true"></div>

<video class="absolute inset-0 w-full h-full object-cover" poster="/thumbnails/video-poster.jpg" playsinline preload="metadata"

<source src="video.mp4" type="video/mp4" />

</video> </div>

<!-- Responsive grid of video thumbnails with zero CLS --> <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4"> <div class="aspect-video overflow-hidden rounded-lg bg-gray-900"> <video class="w-full h-full object-cover" poster="/thumb1.jpg" preload="none" playsinline></video> </div> <div class="aspect-video overflow-hidden rounded-lg bg-gray-900"> <video class="w-full h-full object-cover" poster="/thumb2.jpg" preload="none" playsinline></video> </div> <div class="aspect-video overflow-hidden rounded-lg bg-gray-900"> <video class="w-full h-full object-cover" poster="/thumb3.jpg" preload="none" playsinline></video> </div> </div>

Full-Bleed Video on Mobile, Constrained on Desktop

<!-- Full-width on mobile, centered with max-width on desktop --> <div class="w-full lg:max-w-4xl lg:mx-auto"> <div class="aspect-video overflow-hidden lg:rounded-xl bg-black"> <video class="w-full h-full object-cover" playsinline preload="metadata"> <source src="hero.mp4" type="video/mp4" /> </video> </div> </div>

<!-- Full-bleed hero video background --> <section class="relative w-full h-screen overflow-hidden"> <video class="absolute inset-0 w-full h-full object-cover" autoplay muted loop playsinline preload="auto"

<source src="hero-bg.mp4" type="video/mp4" />

</video>

<!-- Content overlay with safe padding --> <div class="relative z-10 flex items-center justify-center h-full px-4 sm:px-8"> <div class="text-center text-white max-w-2xl"> <h1 class="text-3xl sm:text-4xl lg:text-6xl font-bold">Hero Title</h1> <p class="mt-4 text-lg sm:text-xl">Subtitle text</p> </div> </div>

<!-- Dark overlay for text readability --> <div class="absolute inset-0 bg-black/40" aria-hidden="true"></div> </section>

Safe Zone Overlays for Video UI

Video player controls and UI elements need touch-friendly sizing and proper placement:

<!-- Custom video player with touch-safe controls --> <div class="@container relative aspect-video overflow-hidden rounded-lg bg-black group"> <video class="w-full h-full object-cover" playsinline preload="metadata"> <source src="video.mp4" type="video/mp4" /> </video>

<!-- Play/Pause overlay - centered, touch-friendly --> <button class=" absolute inset-0 flex items-center justify-center bg-black/0 group-hover:bg-black/20 transition-colors "> <span class=" w-16 h-16 sm:w-20 sm:h-20 flex items-center justify-center rounded-full bg-white/90 shadow-lg "> <svg class="w-8 h-8 sm:w-10 sm:h-10 text-gray-900 ml-1" viewBox="0 0 24 24" fill="currentColor"> <path d="M8 5v14l11-7z"/> </svg> </span> </button>

<!-- Bottom controls bar - respects touch targets --> <div class=" absolute bottom-0 inset-x-0 bg-gradient-to-t from-black/80 to-transparent p-3 sm:p-4 flex items-center gap-3 opacity-0 group-hover:opacity-100 transition-opacity "> <!-- Progress bar - tall enough for touch --> <div class="flex-1 h-1 bg-white/30 rounded-full cursor-pointer"> <div class="h-full w-1/3 bg-white rounded-full relative"> <span class="absolute right-0 top-1/2 -translate-y-1/2 w-4 h-4 bg-white rounded-full -mr-2"></span> </div> </div>

<!-- Time display -->
<span class="text-white text-xs sm:text-sm tabular-nums shrink-0">1:23 / 4:56</span>

<!-- Fullscreen button - touch-friendly minimum size -->
<button class="min-h-11 min-w-11 flex items-center justify-center text-white">
  <svg class="w-5 h-5" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
    <path d="M8 3H5a2 2 0 0 0-2 2v3m18 0V5a2 2 0 0 0-2-2h-3m0 18h3a2 2 0 0 0 2-2v-3M3 16v3a2 2 0 0 0 2 2h3"/>
  </svg>
</button>

</div> </div>

Container Queries for Adaptive Video Players

Video player components that adapt their layout based on container size --- useful when the same player appears in a sidebar, main content area, or modal:

<!-- Video player that adapts to its container --> <div class="@container"> <div class=" flex flex-col @lg:flex-row gap-4 @lg:gap-6 bg-gray-950 rounded-xl overflow-hidden "> <!-- Video area --> <div class=" w-full @lg:flex-1 aspect-video overflow-hidden "> <video class="w-full h-full object-cover" playsinline preload="metadata"> <source src="video.mp4" type="video/mp4" /> </video> </div>

<!-- Info panel - below video on narrow, beside on wide -->
<div class="
  p-4 @lg:p-6
  @lg:w-80 @lg:overflow-y-auto
  text-white
">
  <h3 class="text-base @lg:text-lg font-semibold">Video Title</h3>
  <p class="text-sm text-gray-400 mt-2 line-clamp-2 @lg:line-clamp-none">
    Video description that shows more text when the container is wider...
  </p>

  <!-- Related videos - hidden in narrow containers -->
  <div class="hidden @xl:block mt-6 space-y-3">
    <h4 class="text-sm font-medium text-gray-300">Related</h4>
    <div class="space-y-2">
      <div class="flex gap-3">
        <div class="w-28 aspect-video bg-gray-800 rounded shrink-0"></div>
        <div class="text-xs text-gray-400">Related Video 1</div>
      </div>
    </div>
  </div>
</div>

</div> </div>

Best Practices Summary

Practice Implementation

Mobile-first utilities Unprefixed first, then sm: , md: , lg:

Touch targets min-h-11 min-w-11 (44px minimum)

Fluid typography clamp(min, preferred, max) with rem + vw

Fluid spacing clamp() for padding and margins

Container queries @container for component responsiveness

Safe areas env(safe-area-inset-*) for notched devices

Readable text max-w-prose (65ch) and leading-relaxed

Lazy loading loading="lazy" on below-fold images

Touch spacing gap-3 (12px) minimum between targets

Viewport meta width=device-width, initial-scale=1