Frontend Design System - Yosemite Crew

Description

Use this skill when working on UI in apps/frontend. It teaches you how to use our custom design system, component library, and style conventions so you produce consistent, on-brand UI without reinventing the wheel.

TRIGGER: any task involving JSX, styling, layout, new components, or visual changes in apps/frontend.

Core Rule: Reuse Before Creating

Before writing any new UI element, search the existing component library.

src/app/ui/                 ← start here
  Button.tsx                ← variants: primary | secondary | danger
  Card.tsx                  ← variants: default | bordered | subtle
  Badge.tsx                 ← non-status labels (status chips use StatusPill)
  Input.tsx                 ← base input with token borders
  Stack.tsx                 ← flex layout helper
  Text.tsx                  ← typography variants
  inputs/                   ← Datepicker, Dropdowns, Search, FileInput
  cards/                    ← Appointment, Inventory, Forms, etc.
  tables/                   ← DataTable variants
  overlays/                 ← Modal, Toast, Loader
  layout/                   ← Header, Sidebar, guards
  primitives/Buttons/       ← Primary, Secondary, Delete (low-level)
  primitives/StatusPill/    ← THE status pill (tone-coloured, uppercase)
  primitives/SegmentedPill/ ← segmented pill controls (view/tab toggles)
  filters/                  ← Forms, Inventory, general filters
  board/                    ← kanban board components
  widgets/                  ← domain widgets

Import from the barrel: import { Button, Card, Badge } from '@/app/ui'

Design Tokens

The design-token source of truth is apps/frontend/src/app/globals.css - the Tailwind @theme block PLUS the runtime layers below it: :root (the warm-bone light palette: --blue, --ink, --screen, --band, --hairline, ...) and html[data-theme="dark"]. The short-form tokens outnumber --color-* in app code roughly 3:1, so "use --color-*" is not the rule - match the token layer the surrounding code uses (apps/frontend/AGENTS.md has the full token-layer map). Never hardcode hex values or px sizes - always use tokens.

/* Colors */
--color-*                                    (Tailwind @theme, e.g. --color-neutral-200)
--blue, --ink, --screen, --band, --hairline  (warm-bone runtime layer: :root + html[data-theme="dark"])

/* Typography */
--font-satoshi     (body/UI - all weights 300-900)
--font-newsreader  (display serif - page titles, marketing moments)

Satoshi is the body/UI font; Newsreader (--font-newsreader, applied via .text-page-title / .font-newsreader) is the display serif for page titles and marketing moments. The durable rule: never re-add --font-grotesk or --grotesk-font (see src/app/ui/tokens.md).

Reference documentation: src/app/ui/tokens.md (derived guide, not source of truth)

Styling Rules

• Tailwind CSS 4 is the styling system. Use utility classes.
• Use clsx for conditional class composition - it's already in the project.
• Never write inline style={{}} unless a value cannot be expressed as a token.
• Never add raw Bootstrap classes to new code - Bootstrap is legacy, do not spread it.
• Never use arbitrary Tailwind values (e.g. w-[347px]) unless strictly required for pixel-perfect alignment from design specs.

Class ordering (Tailwind)

Layout → Spacing → Sizing → Typography → Colors → Borders → Effects → Responsive

Typography

Use the <Text> component for all copy, not bare <p> / <span> tags.

Body/UI font: Satoshi (300 Light → 900 Black). Display serif: Newsreader for page titles and marketing moments (.text-page-title in globals.css applies it). Never default to Inter, Roboto, or system fonts for new UI.

UI Text Normalization

• Never show raw backend enums, acronyms, or short forms in user-visible copy (for example PAYMENT_AT_CLINIC, VET, PMS).
• Always map domain values to plain-language labels before rendering.
• Do not use Actor as a user-facing label. Use contextual labels such as Lead/Support, or neutral Updated by when role context is unknown.

Component Patterns

Creating a new component

1. Search src/app/ui/ - if something similar exists, extend it.
2. If a new primitive is needed, place it in src/app/ui/ alongside its peers.
3. Domain-specific components go in the relevant features/ subdirectory.
4. Use TypeScript props with named types (no inline { prop: type } in function signatures).

Button usage

// Always use the wrapper, not primitives directly.
// Omit href for actions - href renders an <a> (Next.js Link); use it only for navigation.
<Button variant="primary" text="Save" onClick={handleSave} />
<Button variant="secondary" text="Cancel" onClick={handleCancel} />
<Button variant="danger" text="Delete" onClick={handleDelete} />

State management

Use Zustand stores in src/app/stores/. Each domain has its own store. Do not introduce new state management libraries.

Available stores: appointment, appointmentWorkspace, auth, availability, companion, counter, document, forms, fullscreenLoader, integration, inventory, invoice, org, parent, profile, revampCatalog, room, routeLoader, search, service, signingOverlay, speciality, subscription, task, team, universalSearch. Lists drift — enumerate src/app/stores/ before creating any store.

Gotchas

• Do not nest <button> inside <button> - invalid HTML, breaks tests.
• Do not put icons in <button> mocks in tests - use <span> not <button> for react-icons mocks.
• Bootstrap classes are legacy; do not add new ones - Tailwind only for new code.
• Never use --font-* values that don't exist in globals.css - check before using.
• Never duplicate a store - check src/app/stores/ before creating new state.
• clsx not cn, classnames, or template literals for conditional classes.
• The design system does NOT use shadcn, Radix, or Material-UI - do not import them.

References

• Token source of truth: apps/frontend/src/app/globals.css
• Token map (reference): src/app/ui/tokens.md
• Component map: src/app/ui/README.md
• Detailed API signatures: references/components-api.md