Mobile-First Design: Best Practices for 2025

Introduction

Most sessions start on mobile. Designing mobile‑first forces clarity, improves performance budgets, and simplifies hierarchy across all breakpoints.

Layout & Hierarchy

• One primary CTA per screen; secondary actions demoted.
• Chunk content with clear headings; use line length ~45–75 chars.
• Prefer bottom‑anchored actions for thumb reach.

Inputs & Touch

• Touch targets ≥44×44px with 8px spacing.
• Use appropriate mobile keyboards via input types and inputmode.
• Persist critical state across navigation and refresh.

Navigation

• Keep global nav shallow; highlight current location.
• Use sticky headers for context; avoid excessive nesting.

Performance

• Set budgets (e.g., LCP ≤ 2.5s on 4G, JS ≤ 200KB).
• Optimize images (modern formats, responsive sizes, lazy loading).
• Defer non‑critical JS; prefetch likely routes.

Conclusion

Mobile‑first is clarity‑first. Constrain early, scale intentionally, and your desktop experience will benefit too.