Personal training, without the gym.

We built a Next.js 15 monorepo with three surfaces sharing a design system: a client portal, a trainer portal, and an admin.

The design language came first. Canela as the display face, Matter as the body, no border-radius on anything, no drop shadows anywhere. Four color tokens — ink, cream, stone, warm — and a single accent used sparingly. It reads like an editorial page, not an app. Every micro-decision defended the aesthetic.

Stripe billing at three tiers ($520 / $980 / $1,380), with pause, downgrade, and cancel flows on the client side. Supabase as the database with row-level security on every table — a trainer can only see their own clients, an admin can see everything, a client can only see themselves. Not enforced in code — enforced in Postgres.

Trainer onboarding is the credential system in disguise. Thirteen locked PDF modules, each requiring the trainer to scroll to the bottom before the "acknowledge" button unlocks, type their legal name to sign, and pass a timestamped acknowledgment that lands in the audit table. Substitute trainers can be onboarded in half a day instead of three.

The before/after progress slider is the moment we knew the design was working. Two photos, a draggable divider, three key numbers below. Trainers pull it up during check-ins. Clients screenshot it and post to Instagram. The slider does the marketing.