generate-ui-from-brand（从品牌生成 ui）

generate-ui-from-brand

Type: Pipeline / Orchestrator Input: URL or existing DESIGN.md Output: Actionable UI spec with decisions made

Step 1 — Extract

If a URL is provided and Dembrandt MCP is available:

get_design_tokens(url)
get_color_palette(url)
get_typography(url)
get_component_styles(url)
get_spacing(url)

If Dembrandt MCP is not available, run CLI:

npx dembrandt <url> --design-md --pages 3

If DESIGN.md already exists: parse it directly — skip extraction.

Step 2 — Normalize Tokens

Do not use raw extracted values directly. Map them to a semantic system first.

Colours

Identify the role of each extracted colour:

Decision rule: if the extracted palette has more than 2 brand colours competing for color-primary, pick the one with highest usage on interactive elements.

Typography

Map extracted sizes to a scale. Verify ratio coherence — if sizes do not follow a consistent ratio, round them to the nearest modular scale step (base 16px, ratio 1.25 recommended).

Decision rule: if extracted body text is below 16px, override to 16px.

Spacing

Identify the base spacing unit from the most common small margin/padding value. Derive a scale:

base = extracted smallest recurring value (usually 4px or 8px)
scale = base × 1, 2, 3, 4, 6, 8, 12, 16

Border Radius

Extract the most common radius value used on interactive elements (buttons, inputs). This becomes --radius-button — applied uniformly to all buttons regardless of variant.

Step 3 — Apply UX Decisions

With normalized tokens, make the following decisions explicitly. Do not leave these open:

Visual Hierarchy

• Identify the single primary action for the UI being built
• Assign color-primary to that action only
• All other actions use neutral or outlined styles
• Apply cursor: pointer to all interactive elements

Gestalt Grouping

• Define spacing between related elements (tight: space-2) and between groups (loose: space-6 or space-8)
• Confirm that related controls will be co-located in the layout

Accessibility (WCAG 2.2 AA)

Run contrast check on normalized tokens:

• color-text on color-surface: must be ≥ 4.5:1
• color-text-secondary on color-surface: must be ≥ 4.5:1
• color-primary on white/surface (button label): must be ≥ 4.5:1

If any fail, darken or lighten the token to meet the threshold. Document the adjustment.

Error / Status Colours

• Confirm color-error is red and used only for errors
• Confirm color-warning is orange/amber and used only for warnings
• If the brand uses orange as a primary colour, it cannot double as a warning — a distinct amber must be defined for warning states

Step 4 — Output UI Spec

Produce a concrete, copy-pasteable output. Choose the format that fits the request:

Design Token File (CSS)

:root {
  /* Colours */
  --color-primary:          <value>;
  --color-secondary:        <value>;
  --color-surface:          <value>;
  --color-surface-raised:   <value>;
  --color-border:           <value>;
  --color-text:             <value>;
  --color-text-secondary:   <value>;
  --color-error:            <value>;
  --color-warning:          <value>;
  --color-success:          <value>;

  /* Typography */
  --font-sans:    <extracted font family>;
  --text-base:    1rem;
  --text-sm:      0.875rem;
  --text-lg:      1.25rem;
  --text-h4:      1.563rem;
  --text-h3:      1.938rem;
  --text-h2:      2.438rem;
  --text-h1:      3.063rem;

  /* Spacing */
  --space-1:  <base>px;
  --space-2:  <base×2>px;
  --space-4:  <base×4>px;
  --space-6:  <base×6>px;
  --space-8:  <base×8>px;

  /* Borders */
  --radius-button:  <extracted>px;
  --radius-card:    <extracted or radius-button + 2>px;

  /* Elevation */
  --shadow-card:   0 1px 3px rgba(0,0,0,.10), 0 1px 2px rgba(0,0,0,.06);
  --shadow-modal:  0 10px 15px rgba(0,0,0,.08), 0 4px 6px rgba(0,0,0,.05);
}

UX Audit (if auditing an existing UI)

CONTRAST ISSUES
  - color-text-secondary on color-surface: X.X:1 (required 4.5:1) → fix: darken to #...

HIERARCHY ISSUES
  - 3 primary buttons on same screen → reduce to 1 primary, 2 secondary

CONSISTENCY ISSUES
  - Button radius varies (4px, 8px, 12px) → standardize to --radius-button: 8px

MISSING STATES
  - No disabled state defined for inputs
  - No error state for form fields

FONT SIZE VIOLATIONS
  - Caption text at 12px → minimum 14px

Component Structure (if generating a layout)

Page layout:
  Header (fixed, 56px)
    Logo | Nav | [Global controls: small type]

  Main
    Hero section
      H1 (display scale) + lead text + primary CTA (color-primary, full)

    Feature grid (3-col)
      Card (shadow-card, radius-card) × 3
        Icon + H4 + body text

  Footer
    Links (text-sm, color-text-secondary)
    Language/currency selector (text-sm)

Primary action: CTA button in hero
Secondary actions: nav links, card CTAs (outlined)
Error states: inline, adjacent to field, red text + icon

Audit Checklist Before Handoff

• All tokens named semantically, not by value (color-primary not color-blue-600)
• Body text ≥ 16px everywhere
• Contrast ratios verified for all text/background combinations
• One primary button per view
• All buttons share --radius-button
• cursor: pointer on all interactive elements
• Error colour reserved exclusively for errors
• Warning colour (orange) reserved exclusively for warnings
• Spacing derived from a single base unit