Themes
A Mecsto theme is the entire public website of a real service business — not a skin over one. You design and build every marketing page; the platform renders the money path inside it.
What a theme is
A theme is a Next.js package under packages/themes/<name>. It exports a page component for each route in the page contract, plus two files that describe it to the platform:
theme.json— the manifest: which fields a merchant may edit, which pages exist, and the palette.tokens.ts— your design tokens, which merchant branding feeds into.
Optionally it can also supply an AccountShell (your chrome around the platform’s account pages) and custom pages beyond the contract.
What a theme controls
Layout, typography, colour, motion, imagery, copy structure, and the composition of 15 section types the merchant’s visual editor can place and reorder. In practice: everything a visitor sees before they decide to buy.
What a theme cannot do
Two boundaries are structural rather than advisory.
The money path is not yours. Checkout, login, and the account area are rendered by the platform on every theme. Your links point at /checkout, /login and /account; no theme code executes inside them. This is what lets a theme be reviewed for design rather than audited for payment bugs — read the money path for why.
You never query merchant data. Data arrives through typed loaders returning view-models. There is no table access, no SQL, and no credential in a theme. A theme that cannot reach the database cannot leak it.
Build it entirely offline
The Theme Dev Kit runs a fictional Demo Studio store through the same multi-theme runtime production uses. Every loader serves realistic fixture data. The kit is hard-pinned to demo mode — it cannot talk to a live backend at all, holds no secrets, and needs no Mecsto account.
That means an agency can build, iterate and finish a theme before anyone provisions anything, and what renders locally is what ships.