Claude Code mobile

Responsive Layout Breaks Below 375px Screen Width

Your application's layout breaks on very small screens (below 375px width), even though it looks fine on standard mobile sizes. Elements overflow horizontally, text gets cut off, buttons become untappable, and the page requires horizontal scrolling to use.

This affects users with older or smaller phones (iPhone SE, Galaxy A series), users who have increased their system font size, and users viewing your app in split-screen mode on tablets. These are real users who are completely locked out of your app.

Claude Code typically generates responsive CSS targeting common breakpoints (768px, 640px) but doesn't account for screens smaller than 375px, where fixed pixel widths, min-width declarations, and padding cause layout overflow.

Error Messages You Might See

Horizontal scroll appears on mobile Layout shifts when rotating device Elements overflow viewport boundary Touch targets too small (Lighthouse audit)
Horizontal scroll appears on mobileLayout shifts when rotating deviceElements overflow viewport boundaryTouch targets too small (Lighthouse audit)

Common Causes

  • min-width on containers — CSS rules like min-width: 375px or min-width: 320px prevent the layout from shrinking further
  • Fixed pixel widths — Elements have width: 360px or similar fixed values that can't adapt to smaller screens
  • Horizontal padding overflow — Container padding (e.g., px-8 / 32px on each side) consumes too much of the narrow viewport
  • Flexbox not wrapping — Row layouts with flex-nowrap force elements side by side when they should stack
  • Media queries start too high — The smallest breakpoint is 640px, with no styles for screens below that

How to Fix It

  1. Design mobile-first — Write base styles for the smallest screen, then add complexity with min-width media queries
  2. Replace fixed widths with percentages or max-width — Use width: 100% or max-width: 100% instead of pixel values
  3. Reduce padding on small screens — Use responsive padding like p-3 sm:p-6 to reduce spacing on narrow viewports
  4. Test at 320px width — Use Chrome DevTools responsive mode set to 320px to find overflow issues
  5. Add overflow-x: hidden cautiously — Only on the body element as a safety net, not as a fix for individual layout issues
  6. Use clamp() for font sizes — Replace fixed font sizes with clamp(14px, 4vw, 18px) for fluid typography

Real developers can help you.

Anthony Akpan Anthony Akpan Developer with 8 years of experience building softwares fro startups Mehdi Ben Haddou Mehdi Ben Haddou - Founder of Chessigma (1M+ users) & many small projects - ex Founding Engineer @Uplane (YC F25) - ex Software Engineer @Amazon and @Booking.com ISHANTDEEP SINGH ISHANTDEEP SINGH Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems. Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. BurnHavoc BurnHavoc Been around fixing other peoples code for 20 years. Jen Jacobsen Jen Jacobsen I’m a Full-Stack Developer with over 10 years of experience building modern web and mobile applications. I enjoy working across the full product lifecycle — turning ideas into real, well-built products that are intuitive for users and scalable for businesses. I particularly enjoy building mobile apps, modern web platforms, and solving complex technical problems in a way that keeps systems clean, reliable, and easy to maintain. Victor Denisov Victor Denisov Developer Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. zipking zipking I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify. As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value.

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Frequently Asked Questions

What is the smallest screen width I should support?

Design for 320px as the minimum. This covers iPhone SE, older Android phones, and split-screen tablet usage. Test at 320px during development to catch overflow issues early.

How do I find what's causing horizontal scroll?

In Chrome DevTools, add a temporary style: * { outline: 1px solid red; } to see every element's boundaries. The element extending beyond the viewport edge is your culprit.

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