Reads replica/recon.md and the screenshots in replica/screens/. Writes
replica/design/tokens.json (template in this folder), tokens.css, the
Tailwind mapping, and replica/design/components.md.
python3 contrast.py replica/design/tokens.json # every text pair, WCAG ratio
The rules
What you rebuild is the system: the roles, the scale, the patterns, the way a form or a modal behaves. Those are not ownable, and users expect them. What you never take:
- Logos, icons, illustrations, photos, sounds. Use an open icon set (Lucide, Phosphor, Heroicons, Tabler, all MIT or similar) and make or commission your own illustrations. Do not trace theirs.
- Licensed fonts. If the original uses a paid or proprietary font, pick an open one with the same job: Inter, Geist, IBM Plex, Manrope, Source Serif.
- Their copy. Every label and empty state gets written fresh.
- Their brand colour. Record it as a role (
accent), use a neutral placeholder now, and replica-brand gives you your own. The signature colour plus the signature layout is trade dress, and it changes before launch.
Step 1: measure, do not guess
From the screenshots (zoom in, use a colour picker on the user's machine):
- Colour roles, not colours: bg, surface, border, border-input, text, text-muted, accent, on-accent, danger, success, warning. Count how many greys the app really uses. Usually 5 to 7.
- Type scale: sizes, line heights, weights. Snap to a scale (12, 14, 16, 20, 28, 40 is common). Note the font category, not the font file.
- Spacing: measure gaps between elements. It is almost always a 4 or 8 base. Write the scale.
- Radius, shadow, motion: two or three of each.
- Layout: max content width, grid, breakpoints, sidebar width, header height.
Step 2: write the tokens
Fill tokens.json. Keep the role names. replica-brand only changes values.
Generate tokens.css as custom properties and map them into Tailwind's theme
so components use bg-surface text-muted, never raw hex.
Add a pairs list for every text and background combination the app uses,
then:
python3 contrast.py replica/design/tokens.json
AA is the floor: 4.5:1 for body text, 3:1 for large text and for input borders and focus rings. It exits 1 on a failure. Fix it in the tokens, not per component.
Step 3: component specs
For every component in the recon list, one block in components.md:
Button
variants primary, secondary, ghost, danger
sizes sm 32px, md 40px, lg 48px
states default, hover, active, focus-visible (2px ring, accent), disabled, loading
tokens bg accent, text on-accent, radius md, font sm/600
a11y real <button>, visible focus, loading keeps the label for screen readers
used on S02, S07, S09
Every state the recon saw, plus the ones it should have: focus, disabled, loading, error, empty. Keyboard and screen reader behaviour is part of the spec.
Step 4: build the primitives
Build the components in code once, in isolation (a /design route or
Storybook), before any screen. Use an accessible base if the stack has one
(Radix, shadcn/ui, React Aria). Screenshot the page. That is the design system
check.
Output
tokens.json, tokens.css, the Tailwind config, components.md, the
primitives built, and a contrast report with zero AA failures. Next:
/replica-build.