At Invifest we make invitations and guest management for weddings and every big moment. Each family gets its own invitation website: every function with its date, time, venue and map pin, dress codes, the family's own song, and an RSVP for each function. The link goes out on WhatsApp.

That last part changes everything about how we build. The person opening the link is rarely the couple. It is a grandmother on a four year old Android phone, inside WhatsApp's in-app browser, with battery saver on. Here is what that guest taught us.

1. With every animation switched off, the page must still be whole

Reduce Motion on iPhone, Low Power Mode and Android battery savers stop CSS animations dead. If a block only reaches opacity: 1 through a keyframe, it stays invisible forever for that guest. The same settings make scrollIntoView({ behavior: 'smooth' }) do nothing at all.

Our rule now:

The resting state is visible.…