Build Your Production Page

🔄 Recall Bridge: In the previous lesson, you optimized for Core Web Vitals — LCP, CLS, and INP. Now let’s bring everything together: build a complete page that’s semantic, responsive, accessible, and fast.

This capstone puts all seven lessons into practice. You’ll build a production-quality web page using a staged approach — generating with AI, reviewing against your quality checklist, and fixing every issue until the page meets production standards.

The Staged Build Process

Stage	What You Generate	What You Review
1. HTML Structure	Semantic elements, heading hierarchy, landmarks	No divitis, proper headings, ARIA labels
2. CSS Layout	Grid/Flexbox, design tokens, mobile-first	Responsive from 320px-1920px, dark mode
3. Components	Card, form, navigation (one at a time)	Keyboard support, focus states, ARIA
4. Images & Media	Responsive images, lazy loading	srcset, WebP, CLS prevention
5. Interactions	Animations, dynamic content	Reduced motion, aria-live, INP
6. Performance	Preload, defer, critical CSS	LCP < 2.5s, CLS < 0.1, INP < 200ms

AI prompt for Stage 1 (structure):

Generate the semantic HTML structure for a product landing page with: (1) Header with main navigation (5 links), (2) Hero section with heading, subheading, and CTA button, (3) Features section with 3 feature cards, (4) Pricing section with 3 pricing tiers, (5) Testimonials section with 2 quotes, (6) Footer with secondary navigation and copyright. Use ONLY semantic HTML elements — no <div> where a semantic element exists. Include proper heading hierarchy (one h1, sections with h2, cards with h3). Add ARIA labels for navigation landmarks.

The Production Quality Checklist

Structure & Semantics

One <h1> per page, heading hierarchy sequential (no skipped levels)
Semantic elements used (<nav>, <main>, <article>, <section>, <footer>)
Repeated landmarks have aria-label (multiple <nav> elements)
Images have meaningful alt text (not “image” or “photo”)
Forms have <label> for every input, <fieldset> for groups

Responsive Design

Mobile-first CSS (min-width media queries)
Looks correct at 320px, 375px, 768px, 1024px, 1920px
No horizontal scrollbar at any width
Text readable without zooming on mobile
Touch targets at least 44×44px on mobile

Accessibility

Tab through entire page — logical order, no traps
All interactive elements have visible focus indicators
Color contrast meets WCAG AA (4.5:1 text, 3:1 large text)
Screen reader announces content coherently
Dynamic content changes announced (aria-live)
Works at 200% zoom without content loss
Animations respect prefers-reduced-motion

Performance

LCP < 2.5 seconds
CLS < 0.1 (no layout shifts)
INP < 200ms (responsive to interactions)
Images: srcset + WebP + lazy loading (below fold)
Hero image: preloaded, fetchpriority=“high”
Critical CSS inlined, non-critical deferred
JavaScript deferred or async

Dark Mode & Theming

All colors use CSS custom properties
Dark mode works via prefers-color-scheme: dark
Contrast ratios maintained in dark mode
No hardcoded colors in components

Course Review

Lesson	Core Skill	Key Rule
Semantic HTML	Structure that machines understand	Use the most specific HTML element available
CSS Architecture	Maintainable, token-based styling	Design tokens for every value, Grid for 2D, Flexbox for 1D
UI Components	Reusable building blocks	Native elements first, keyboard patterns always
Responsive Design	Works on every screen	Mobile-first, fluid typography with clamp(), responsive images
Accessibility	Usable by everyone	Automated testing catches 30-40%, manual testing catches the rest
Performance	Fast on any connection	Optimize LCP chain, prevent CLS, defer non-critical resources

Common Mistakes Across All Lessons

Mistake	What AI Does	What You Should Do
Div soup	Wraps everything in `<div>`	Use semantic elements
No keyboard support	Mouse-only interactions	Add keyboard patterns
Hardcoded values	Pixel values everywhere	Use design tokens
Desktop-first CSS	max-width media queries	min-width (mobile-first)
Missing focus styles	`outline: none`	Visible `:focus-visible`
Lazy loading LCP	`loading="lazy"` on hero	`fetchpriority="high"` + preload
No dark mode	Only light theme colors	CSS custom properties
Missing alt text	Empty or generic alt	Descriptive, context-appropriate

✅ Quick Check: You’ve audited your page against the full checklist. Everything passes except: screen reader announces pricing cards in the wrong order (3, 1, 2 instead of 1, 2, 3). The visual order is correct. What causes this? (Answer: CSS order, flex-direction: row-reverse, or grid-template can reorder elements visually without changing DOM order. Screen readers follow DOM order, not visual order. Fix: reorder the elements in HTML to match the visual layout, or use aria-flowto if the visual reorder is essential.)

Your 30-Day Improvement Plan

Week	Focus	Practice
Week 1	Build a complete page using the staged process	Follow the 6-stage build with AI, audit with checklist
Week 2	Rebuild the same page from scratch	Compare: fewer AI-needed fixes, faster audit
Week 3	Build a more complex page (form + dynamic content)	Add error states, loading states, form validation
Week 4	Audit an existing website you use daily	Apply the checklist to real-world pages, note common issues

Key Takeaways

Generate and review in stages (structure → layout → components → interactions → performance), not all at once — each stage is small enough to review thoroughly, issues caught early don’t propagate, and you understand every line you ship
The production quality checklist covers more than the “happy path”: screen reader coherence, error states, loading states, dark mode, 200% zoom, and reduced motion are rendering modes real users depend on — test all of them before deploying
Building and auditing real pages against a checklist is the fastest path to frontend expertise: each failed audit item you fix teaches you something AI missed, and tracking which items you consistently catch vs. miss reveals your specific growth areas

Congratulations

You’ve completed the AI for Frontend Development course. You now understand the fundamentals that make AI-generated code production-ready: semantic HTML for accessibility, modern CSS for maintainable layouts, component patterns for reusable UI, responsive design for every device, accessibility for every user, and performance optimization for every connection. Your next step: build a page, run the checklist, and fix what you find.