A browser profile is not a new engine
Changing viewport dimensions inside Chromium does not turn it into WebKit. Use Viewport Studio for spatial comparison, then verify compatibility in the target browser.
Common sources of differences
- Dynamic address bars and visible height
- Date, search and select controls
- Sticky positioning combined with overflow
- Font loading and line breaks
- New CSS features and prefixes
Use modern viewport units carefully
svh, lvh and dvh help with changing browser chrome, but keep sensible fallbacks. Dialogs and bottom bars must also account for safe areas and virtual keyboards.
Turn past bugs into regression checks
Maintain a short list for Safari forms, iOS navigation height, Firefox scrolling and Android keyboard behaviour. Rechecking known risks is faster than repeating a broad unfocused sweep.