Web Design Methodology
Universal patterns for building production-grade HTML/CSS. This skill covers implementation methodology — pair with web-design-patterns for specific component designs.
What You Produce
Production-ready HTML/CSS prototypes with:
- Semantic CSS custom properties (tokens)
- BEM-named components
- Mobile-first responsive design
- Accessible markup
- Optional three-state dark mode
File Structure
prototype/
├── index.html
├── about.html
├── services.html
├── contact.html
├── favicon.svg
├── css/
│ ├── variables.css # Tokens: colours, typography, spacing
│ ├── styles.css # All component styles (BEM)
│ └── mobile-nav.css # Mobile menu styles
├── js/
│ ├── theme.js # Dark mode toggle (only if requested)
│ └── mobile-menu.js # Hamburger menu
└── media/
└── images/Build order:
variables.css— tokens firstfavicon.svg— simple SVG from brand colourstyles.css— all BEM componentsmobile-nav.css— responsive navigation- JS files — from
assets/templates index.html— homepage first- Inner pages — about, services, contact
- Mobile check — verify at 375px
BEM Naming
Use Block-Element-Modifier naming. No exceptions.
/* Block */
.hero { }
.card { }
.nav { }
/* Element (child of block) */
.hero__title { }
.hero__subtitle { }
.hero__cta { }
.card__image { }
.card__content { }
/* Modifier (variation) */
.hero--split { }
.hero--minimal { }
.card--featured { }
.btn--primary { }
.btn--lg { }Rules:
- Blocks are standalone components
- Elements are children, connected with
__ - Modifiers are variations, connected with
-- - Never nest more than one level:
.hero__content__titleis wrong - Never use element without its block:
.card__imageonly inside.card
CSS Custom Properties
Use semantic tokens. Never hardcode colours, spacing, or typography values.
See references/css-variables-template.md for the complete token template.
/* Always this */
.card {
background: var(--card);
color: var(--card-foreground);
border: 1px solid var(--border);
border-radius: var(--radius);
box-shadow: var(--shadow-sm);
padding: var(--space-6);
}
/* Never this */
.card {
background: #ffffff;
color: #333333;
border: 1px solid #e5e5e5;
border-radius: 8px;
box-shadow: 0 1px 3px rgba(0,0,0,0.1);
padding: 24px;
}Dark Mode (Optional)
Dark mode is optional — only add if the brief requests it. Most business sites ship faster as light-only.
When to include:
- Brief explicitly requests it
- Tech/developer audiences (expected)
- Portfolio/creative sites (aesthetic choice)
When to skip:
- Trades, hospitality, professional services
- When simplicity and fast shipping matter more
If Adding Dark Mode
Use class-based toggle, never CSS media queries.
/* Light mode (default) */
:root {
--background: #F9FAFB;
--foreground: #0F172A;
--card: #FFFFFF;
--card-foreground: #1E293B;
}
/* Dark mode (via .dark class on html) */
.dark {
--background: #0F172A;
--foreground: #F1F5F9;
--card: #1E293B;
--card-foreground: #F1F5F9;
}Rules:
.darkclass on<html>, toggled via JavaScript- NEVER use
@media (prefers-color-scheme: dark)— JS handles system preference - Every background token needs a paired foreground token
- Brand colours get lighter/more saturated in dark mode
- Backgrounds:
#0F172Ato#1E293Brange (not pure black) - Every text-on-background combo must pass WCAG AA (4.5:1)
Use assets/theme-toggle.js for the three-state toggle implementation.
Responsive Design
Mobile-first. Design for 375px, enhance upward.
Breakpoints
/* Base: 375px (mobile) — no media query needed */
@media (min-width: 640px) { /* sm — large phone */ }
@media (min-width: 768px) { /* md — tablet */ }
@media (min-width: 1024px) { /* lg — small desktop */ }
@media (min-width: 1440px) { /* xl — standard desktop */ }Mobile Priorities
- Phone number visible and tappable without scrolling
- Primary CTA visible without scrolling
- Navigation works via hamburger menu
- Touch targets minimum 44x44px
- No horizontal scrolling ever
- Images scale properly (no overflow)
Wide Screen Constraints
.prose { max-width: 65ch; }
.hero__content { max-width: min(640px, 45vw); }
.container {
max-width: 1280px;
margin-inline: auto;
padding-inline: var(--space-4);
}
.section { padding: clamp(3rem, 6vw, 6rem) 0; }Use assets/mobile-nav.js for the hamburger menu implementation.
Typography Rules
- Dramatic size contrast. Headlines 3-4x body size.
clamp(2.5rem, 6vw, 5rem)for hero titles. - Weight variety. Mix 300 and 800 weights. Uniform weight is boring.
- One display moment per page. One oversized word, one dramatic headline, one pull quote. Not three.
- Left-align body text. Centre only for heroes and short statements. Never centre paragraphs.
- Letter spacing on uppercase. Add
letter-spacing: 0.05emminimum.
Colour Usage
The 80/20 rule:
- 80% neutral tones (backgrounds, text, cards)
- 15% secondary/muted brand tones
- 5% primary brand colour (CTAs, one accent per viewport)
If primary is on every heading, border, icon — nothing stands out.
Spacing System
Not uniform padding. Sections breathe differently:
/* Tight section (service list, FAQ) */
.section--compact { padding: clamp(2rem, 4vw, 4rem) 0; }
/* Standard section */
.section { padding: clamp(3rem, 6vw, 6rem) 0; }
/* Breathing room (editorial break, testimonial) */
.section--spacious { padding: clamp(4rem, 8vw, 10rem) 0; }Shadow System
| Element | Shadow |
|---|---|
| Cards at rest | --shadow-sm |
| Cards on hover | --shadow-md |
| Dropdowns | --shadow-lg |
| Modals | --shadow-xl |
Not everything needs shadow. Use sparingly.
Icons
Use Lucide icons via inline SVG:
- Size: 24px inline, 32-48px for feature blocks
- Stroke width: 1.5 or 2 (consistent throughout)
- Colour:
currentColor(inherits text colour) - Each icon should communicate something specific
Accessibility
Non-negotiable:
- Semantic HTML:
<header>,<nav>,<main>,<section>,<footer> - Alt text: Meaningful for content images, empty for decorative
- Contrast: 4.5:1 minimum (7:1 preferred)
- Focus styles: Visible on all interactive elements
- Skip link: First focusable element
- Form labels: Associated with inputs
- ARIA:
aria-expandedon toggles,aria-labelwhere needed
Performance
loading="lazy"on images below the foldloading="eager"on hero image<link rel="preconnect" href="https://fonts.googleapis.com">in head- Keep CSS under 50KB total
- No JavaScript frameworks — vanilla JS only
Anti-AI Patterns
These patterns signal "AI generated this" — avoid:
- Hero → trust bar → 3 cards → features → stats → CTA → footer (the skeleton)
- Every section has identical padding
- All cards same size in perfect 3-column grid
- Everything centred
- Every section: heading + subheading + content (same rhythm)
- Decorative elements with no purpose
- "Learn More" as every CTA
- Inter/Arial/system fonts with no typographic personality
Quality Checklist
Before marking complete:
- Direction is clear — can describe aesthetic in one phrase
- Typography makes a statement — not Inter/system
- Colour is restrained — primary used sparingly
- No two adjacent sections look the same
- CTAs are specific — no "Learn More"
- Mobile works — tested at 375px
- Dark mode works (only if enabled) — every section checked
- No hallucinated images — only real file paths
- Would a designer claim this as their work?