Mobile-First Debugging That Sticks

The trap

Desktop Chrome — and even responsive mode — miss touch quirks, 100vh issues, and Safari-specific behavior. I only caught this bug on a physical phone, which is exactly where users live.

Process

1. Reproduce on a real device with remote debugging.
2. Remove dev-only branches from production bundles.
3. Verify focus and scroll behavior when modals or drawers open.

Outcome

A short list of layout rules (min touch targets, predictable overflow) kept me from re-learning the same lessons on every new feature.