UX Prototyping Skill

UX Prototyping Skill

Create single-file HTML prototypes focused on validating user flows, interaction patterns, and information architecture. Prioritize UX fidelity over visual polish.

Workflow

1. Read the UX spec at specs/​architecture/​ux.md (or user-specified path)
2. Identify core flows - Extract user journeys, screens, states, and interactions
3. Build prototype - Create single HTML file with all screens and interactions
4. Output - Save to /​mnt/​user-data/​outputs/​prototype.html

Prototype Structure

Generate a single HTML file containing:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>[App Name] - UX Prototype</​title>
  <style>/​* All CSS inline */</​style>
</​head>
<body>
  <!-- All screens as sections -->
  <!-- Navigation/​state management -->
  <script>/​* All JS inline */</​script>
</​body>
</​html>

Core Principles

UX First, UI Second

• Do: Implement all user flows, states, transitions, error states, empty states
• Do: Make interactions feel responsive and logical
• Do: Show realistic data and content hierarchy
• Defer: Pixel-perfect styling, animations, brand colors (use clean defaults)

Screen Management Pattern

Implement screens as <section> elements with data-screen attributes:

function showScreen(screenId) {
  document.querySelectorAll('[data-screen]').forEach(s => s.hidden = true);
  document.querySelector(`[data-screen="${screenId}"]`).hidden = false;
}

State Management Pattern

Use a simple state object:

const state = { currentScreen: 'home', user: null, data: [] };
function setState(updates) { Object.assign(state, updates); render(); }

Essential UX Elements

1. User Flows

• Primary task completion paths
• Alternative/​secondary flows
• Error recovery flows

2. Screen States

• Empty - First-time user, no data
• Loading - Skeleton or spinner
• Error - Network/​validation errors
• Success - Confirmations
• Partial - Some data loaded

3. Interactions

• Form inputs with validation
• Button states (hover/​active/​disabled)
• Screen navigation
• Modal/​overlay behaviors

Base Styles

* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #f8fafc; --surface: #fff; --text: #1e293b;
  --text-muted: #64748b; --primary: #3b82f6; --border: #e2e8f0;
  --success: #22c55e; --error: #ef4444; --radius: 8px;
}
body { font-family: system-ui, sans-serif; background: var(--bg); color: var(--text); }
[data-screen] { display: none; }
[data-screen].active { display: block; }
.card { background: var(--surface); border-radius: var(--radius); padding: 1.5rem; box-shadow: 0 1px 3px rgba(0,0,0,0.1); }
.btn { padding: 0.625rem 1.25rem; border-radius: var(--radius); font-weight: 500; cursor: pointer; border: none; }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: #2563eb; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }
.input { width: 100%; padding: 0.625rem; border: 1px solid var(--border); border-radius: var(--radius); }
.input:focus { outline: none; border-color: var(--primary); }
.container { max-width: 480px; margin: 0 auto; padding: 1rem; }
.stack > * + * { margin-top: 1rem; }
.empty-state { text-align: center; padding: 3rem; color: var(--text-muted); }
.error-msg { color: var(--error); font-size: 0.875rem; }

Validation Checklist

Before delivering, verify:

• All screens from spec implemented
• Primary flow completable end-to-end
• Empty/​error/​loading states shown
• Navigation works correctly
• Interactive elements have feedback
• Responsive on mobile viewport

Output

Save to /​mnt/​user-data/​outputs/​prototype.html (or descriptive name like prototype-onboarding.html).