Mobile-First Debugging That Sticks

The trap

Desktop Chrome and even responsive mode miss touch quirks, 100vh issues, and Safari-specific behavior. The bug only showed up on a physical phone.

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) prevented repeat regressions in later features.