make_post_sell/docs/design-system.md

MPS Design System

Overview

Make Post Sell uses a design token architecture with CSS custom properties as the single source of truth. Mobile-first. CSS Grid only (no Flexbox). Accessible. Respects reduced motion. Supports light and dark themes.

Architecture Diagram

┌─────────────────────────────────────────────────────────┐
│                    tokens.css                            │
│              Design Tokens (:root)                       │
│                                                          │
│  Colors · Typography · Spacing · Shape · Elevation       │
│  Motion · Z-index · Layout · State overlays              │
│                                                          │
│  [data-theme="dark"] overrides                           │
│                                                          │
│  Base resets · Focus · Selection                         │
│  Typography utilities (.type-*)                          │
│  Elevation utilities (.elevation-*)                      │
│  Surface utilities (.surface-*)                          │
│  State layer · Ripple effect                             │
│  Animations · Skeleton loading · Spinner                 │
│  Spacing utilities (.mt-*, .mb-*, .p-*, .gap-*)         │
│  Container utilities (.container, -narrow, -wide)        │
└──────────────────────┬──────────────────────────────────┘
                       │ consumed by
                       ▼
┌─────────────────────────────────────────────────────────┐
│                    common.css                            │
│              Component Styles                            │
│                                                          │
│  Body layout · Navigation · Forms · Buttons              │
│  Product grid · Cards · Cart · Comments                  │
│  Wells · Alerts · Ribbons · Footer                       │
│  Watch mode · Landing page · Login                       │
│  Responsive breakpoints                                  │
│                                                          │
│  References tokens via var(--token-name, fallback)       │
└──────────────────────┬──────────────────────────────────┘
                       │ rendered in
                       ▼
┌─────────────────────────────────────────────────────────┐
│                   templates/                             │
│              Jinja2 Templates                            │
│                                                          │
│  base.j2 → theme toggle, nav, footer                    │
│  styleguide.j2 → live component reference               │
│  product.j2, content.j2, shop.j2, etc.                  │
└─────────────────────────────────────────────────────────┘

File Map

File	Lines	Purpose
static/css/tokens.css	775	Design tokens, utilities, animations, resets
static/css/common.css	3879	Component styles consuming tokens
templates/styleguide.j2	1083	Live styleguide at /styleguide
views/misc.py:23	—	Styleguide view controller

Token Categories

Colors

Brand           Surface              Text                Border
──────────      ──────────           ──────────          ──────────
--color-green   --surface-base       --text-primary      --border-default
--color-blue    --surface-dim        --text-body         --border-light
--color-navy    --surface-container  --text-secondary    --border-focus
--color-purple  --surface-container- --text-muted        --border-error
--color-danger    high               --text-faint
--color-gold    --surface-inverse    --text-disabled
                                     --text-inverse

Typography Scale (Major Third 1.250)

Token          Size     Use
──────────     ──────   ──────────────────────
--text-xs      12px     Captions, overlines
--text-sm      14px     Labels, small body
--text-base    16px     Body text (root)
--text-md      18px     Large body
--text-lg      20px     Titles
--text-xl      24px     Title large
--text-2xl     30px     Headline 3
--text-3xl     36px     Headline 2
--text-4xl     48px     Headline 1
--text-5xl     60px     Display

Spacing Scale (4px base)

Token          Value
──────────     ──────
--space-0      0
--space-1      4px
--space-2      8px
--space-3      12px
--space-4      16px
--space-5      20px
--space-6      24px
--space-8      32px
--space-10     40px
--space-12     48px
--space-16     64px
--space-20     80px
--space-24     96px

Shape (Border Radius)

--radius-none   0        Sharp corners
--radius-sm     4px      Inputs, code blocks
--radius-md     8px      Cards, buttons
--radius-lg     12px     Modals, panels
--radius-xl     16px     Large surfaces
--radius-2xl    24px     Pills
--radius-full   9999px   Circles

Elevation (Box Shadow)

--elevation-0   none       Flat
--elevation-1   subtle     Cards at rest
--elevation-2   low        Raised cards
--elevation-3   medium     Dropdowns
--elevation-4   high       Modals
--elevation-5   highest    Popovers

Motion

Durations                    Easing
──────────────────           ──────────────────
--duration-instant   50ms    --ease-standard    general transitions
--duration-fast      100ms   --ease-decelerate  entrances
--duration-normal    200ms   --ease-accelerate  exits
--duration-slow      300ms   --ease-emphasize   emphasis
--duration-slower    400ms   --ease-spring      playful bounce
--duration-entrance  250ms
--duration-exit      200ms

Z-Index Scale

--z-base       0      Default stacking
--z-dropdown   100    Dropdowns, popovers
--z-sticky     200    Sticky headers
--z-overlay    300    Overlays, backdrops
--z-modal      400    Modals
--z-toast      500    Toast notifications
--z-ribbon     600    Shop ribbon banner

Layout Breakpoints

--content-narrow   400px    Login forms, narrow content
--content-width    800px    Default content width
--content-wide     1200px   Wide layouts
--bp-tablet        800px    Tablet breakpoint
--bp-desktop       1200px   Desktop breakpoint

Theme System

Light mode is default (:root). Dark mode activates via [data-theme="dark"] on the <html> element. The dark theme overrides all semantic tokens — surfaces, text, borders, brand colors — so components adapt automatically without per-component dark mode rules.

Light                           Dark
──────────────────────          ──────────────────────
--surface-base: #FFFFFF         --surface-base: #0d1117
--text-primary: #333333         --text-primary: #ffffff
--border-default: #e0e0e0      --border-default: #7ab9ff
--color-green: #a3c765          --color-green: #08e700
--color-navy: #5871ad           --color-navy: #7ab9ff

Theme toggle: window.setTheme('dark') / window.setTheme('light').

Typography Utilities

CSS classes that compose token values into complete type styles:

Class	Size	Weight	Use
.type-display	clamp(36px, 5vw, 60px)	bold	Hero headlines
.type-headline-1	48px	bold	Page titles
.type-headline-2	36px	bold	Section titles
.type-headline-3	30px	bold	Subsection titles
.type-title-lg	24px	semibold	Card titles
.type-title	20px	semibold	List titles
.type-title-sm	16px	semibold	Small titles
.type-body-lg	18px	regular	Lead paragraphs
.type-body	16px	regular	Body text
.type-body-sm	14px	regular	Secondary text
.type-label-lg	14px	semibold	Form labels
.type-label	12px	semibold, uppercase	Overline labels
.type-caption	12px	regular	Captions
.type-overline	11px	bold, uppercase	Section overlines
.type-code	0.9em	mono	Inline code

Component Library

All components are documented with live examples at /styleguide. The styleguide is the single source of truth for the component library. If it is not in the styleguide, it does not exist as a pattern.

Styleguide Sections

Section	ID	Description
Tokens	#tokens	Raw token reference table
Colors	#colors	Brand, surface, text, border, alert swatches
Typography	#typography	Type scale and utility classes
Elevation	#elevation	Shadow levels
Motion	#motion	Animations, transitions, easing
Spacing	#spacing	Spacing scale visualization
Shape	#shape	Border radius samples
States	#states	Interactive state layers
Loading	#loading	Skeleton and spinner patterns
Buttons	#buttons	Button variants (green, blue, red, navy, outline)
Forms	#forms	Input fields, textareas, selects, settings-form (.settings-form / .settings-form-grid / .settings-field / .settings-field-hint)
Wells	#wells	Content wells and containers
Alerts	#alerts	Success, info, warning, danger alerts
Status	#status	Status indicators
Product Cards	#cards	Product grid cards, profile card (.profile-card-header / .profile-avatar / .profile-handle / .profile-email-reveal), action button grid (.action-columns / .action-button-grid)
Cart	#cart	Cart and checkout components
Gift Cards	#gift-cards	Gift card purchase, balance check, management
Comments	#comments	Comment form and list
Toggle	#toggle	Toggle switches
Ribbon	#ribbon	Shop ribbon banner
Environment Banner	.environment-banner	Staging/dev environment indicator
Trial Banner	.trial-banner	Trial countdown and expiry notice
Task Bar	#taskbar	Task bar component
Layout	#layout	Grid layout patterns
Theme System	#theme	Theme toggle and dark mode
Footer	#footer	Footer component

MPS-20 / MPS-21 components

Class	Where	Description
.cart-negotiation-card	cart.j2	Soft-green "Offer accepted / Auction won" well at the top of a negotiated cart
.cart-negotiation-deadline	cart.j2	Pay-by countdown line inside the negotiation card
.cart-negotiation-pill	cart.j2	"Offer accepted · quantity locked" pill on line items
.offer-pay-cta-actions	offer.j2	Two-col grid: Cancel left, Pay right (stacks on narrow viewports)
.offer-pay-deadline-note	offer.j2	Buyer's "Payment due in 23 hours, 14 minutes" copy
.offer-pay-link-row	offer.j2	Seller's shareable offer-link with Copy button
.offer-respond-deadline-note	offer.j2	"Respond in 5 days, or this offer auto-expires"
.auction-winner-pay	auction.j2	"You won this auction!" well with countdown + pay CTA
.product-add-disabled-note	product.j2	Caption under disabled Add To Cart when active cart is locked
.shop-offers-page	user_offers.j2 + user_bids.j2 + shop_offers.j2	Wider page (max-width 1100px) overriding .one-column for the offers/bids inbox tables
.shop-offers-table	inbox templates	Responsive table; collapses to per-row block list below 720px
.notification-badge	base.j2 + /u/settings	Danger-color pill showing unread notification count
.notification-row + .notification-row-unread	user_notifications.j2	Notification list rows; read rows fade to 0.65 opacity, unread rows get an alert-info background + navy left border
.notification-row-breadcrumbs	user_notifications.j2	Shop › Product › Offer/Auction/Invoice chain under each row
.billing-page / .billing-paypal-card / .billing-actions	billing.j2	/billing redesigned with Grid + tokens (no inline styles)
[data-pay-deadline]	offer + auction + cart	Convention attribute the shared static/js/pay-countdown.js (and inline tickers in offer.js / auction.js) rewrite once per second with a prose human delta ("in 23 hours, 14 minutes, 8 seconds") matching the server-rendered ago.human() fallback

CSS Conventions

Layout

• CSS Grid only — never use Flexbox for layout
• Mobile-first: base styles target mobile, @media queries enhance for larger screens
• Primary breakpoint: max-width: 800px for mobile

Token Consumption

Components in common.css reference tokens with fallbacks:

/* Good — token with fallback for resilience */
background-color: var(--surface-base, #ffffff);
border-radius: var(--radius-sm, 4px);

/* Good — token without fallback (tokens.css always loaded) */
padding: var(--space-4);

Media Sizing

Never combine width: 100% with max-height on media elements. Use:

/* Correct */
width: auto;
max-width: 100%;
max-height: 33vh;

/* Wrong — creates dead whitespace */
width: 100%;
max-height: 33vh;

Mobile Usability

Never use hover-only interactions. All interactive elements must be always visible and tappable. Design touch-first, then optionally enhance for desktop hover.

Reduced Motion

All animations respect prefers-reduced-motion: reduce via a global media query in tokens.css that collapses durations to near-zero.

Capability-Driven Presentation

Follow Russell Ballestrini's capability-driven presentation practice. A page need not look identical across all browsers. Accommodate what the user's browser can do. Use the js-only / <noscript> pattern for progressive enhancement.

Adding New Components

1. Define the component styles in common.css, consuming tokens from tokens.css
2. Add a live example to /styleguide (templates/styleguide.j2)
3. If the component participates in watch mode SPA navigation, update all three layers: template, watch.js, watch.py

Load Order

base.j2
  └─ <link> static/css/tokens.css     ← tokens + utilities + resets
  └─ <link> static/css/common.css     ← components consuming tokens
  └─ per-page <style> blocks          ← page-specific overrides