A practical workflow for device presets, first-screen checks, and common pitfalls.
Check each device tier one by one
Look at desktop, tablet, and phone separately, focusing on how navigation, tables, and dialogs behave on narrow screens.
Do not only test the two extremes. Middle tiers such as portrait tablets often break too.
Prioritize the first screen, then scrolling content
First-screen content is the most likely to collapse on mobile. Confirm that titles, buttons, and key information do not overlap or truncate.
Some sites block iframe embedding. Open those pages directly in a browser instead.
Use HTML mode as a temporary prototype
You can see how a snippet actually renders without deploying it, which is perfect for quick pre-development validation.
Clean up temporary code after testing so prototype content does not ship.