Signing windows, reminders and delivery
Cards open early, remind stragglers, seal, and deliver at the right local moment.
As a person's date approaches, their card opens for signing for the number of days you chose. Inside the final 24 hours, teammates who haven't signed get one final call (paid plans, when you've written a final-call message). When the window closes the card seals, and on the day it delivers at your chosen moment — morning, afternoon or evening — in the celebrant's own timezone.
Reminders rotate the personal link for safety: the newest message always carries the working link.