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Choose Free if you want a signed-in, email-verified preview that now works better on mobile and tablet without changing paid boundaries.
Use one path for lifetime Free, Pro individual access, Institution teaching permission, manual payment reference, or account support. Free requires signup, email verification, login, and protected launch activation.
Mobile and tablet are useful for quick review, but the full teaching surface is richer on a larger screen: side controls, eye canvas, VNG traces, Expert proof, comparison, quiz feedback, and export tools are easier to see together.
Choose Free if you want a signed-in, email-verified preview that now works better on mobile and tablet without changing paid boundaries.
Choose Pro if you need full individual learning access for your own education or review.
Choose Institution for departments, residency programs, workshops, conferences, or classrooms.