Mobile-First Website Design: The 2026 Production Checklist

Mobile-first stopped being a buzzword in 2020 and became table stakes. Yet 6 of every 10 small business sites I audit still feel like a desktop site shrunk down. Here is the actual spec we ship.

Production spec

• Tap targets minimum 44×44px, 48×48px preferred.
• Primary CTA inside the bottom thumb zone (bottom 1/3 of screen).
• Sticky bottom bar with phone + main CTA on commercial intent pages.
• Hero text under 60 characters, subhead under 120.
• Hero image lazy-loaded with explicit width/height to prevent CLS.
• Forms: native input types, autocomplete attributes, single-column.
• LCP under 2.5s on Slow 4G — measured with WebPageTest, not Lighthouse desktop.