Tact

Send a message: it rises out of the composer, translucent until the server takes it, then shows delivered and seen. Send ❤️ or 🎉 on its own, or click one: it celebrates, once per message and once per conversation per 30 seconds. Mira's replies rise with a wash; four at once is a batch and lands still, as opening a conversation does. Add a reaction to one she started and it swells into the pile; hers only roll the count.

Springs

Material 3's own spring tokens, sampled into CSS linear() until they rest within 0.5%. Components name a role; the level decides what it means: Calm plays each on the standard curve in 140-200 ms, Still makes it instant.

Interface sounds

Soft mallet tones, every one quieter than the message chime; the two ticks are quieter still. Never during a call, in a hidden window, or for someone else's message.

Rules

1. Acknowledge every act within 100 ms, where it happened.
2. The more often something happens, the quieter it is.
3. Motion explains where things came from and where they went.
4. Objects bounce, text does not.
5. Never make anyone wait: exits are faster than entrances, and nothing holds a click.
6. People celebrate, the product does not: no keywords, no milestones, no crowds.
7. One place to tone it down: Settings → Appearance → Motion.