Proper layout and spacing in modern web design — 8px grid systems, modular scales, vertical rhythm, CSS Grid/Flexbox patterns, fluid spacing with clamp(), container queries, and whitespace as design element. Activate on 'spacing', 'layout spacing', 'grid system', 'whitespace', '8px grid', 'vertical rhythm', 'spacing scale', 'gap', 'padding ratio', 'layout primitives', 'responsive spacing', 'clamp spacing', 'container queries layout'. NOT for animation/motion (use motion-design-web), not for color/typography alone (use typography-expert), not for design system creation (use design-system-bootstrap).
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Proper layout and spacing in modern web design — 8px grid systems, modular scales, vertical rhythm, CSS Grid/Flexbox patterns, fluid spacing with clamp(), container queries, and whitespace as design element. Activate on 'spacing', 'layout spacing', 'grid system', 'whitespace', '8px grid', 'vertical rhythm', 'spacing scale', 'gap', 'padding ratio', 'layout primitives', 'responsive spacing', 'clamp spacing', 'container queries layout'. NOT for animation/motion (use motion-design-web), not for color/typography alone (use typography-expert), not for design system creation (use design-system-bootstrap).
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{"category":"Design & UX","tags":["layout","spacing","grid","whitespace","flexbox","css-grid","responsive","design-system","vertical-rhythm"],"pairs-with":[{"skill":"gestalt-web-design","reason":"Proximity and grouping principles drive spacing decisions"},{"skill":"design-system-bootstrap","reason":"Spacing tokens are the foundation of any design system"},{"skill":"hero-section-design","reason":"Hero sections need precise spacing to feel balanced"},{"skill":"typography-expert","reason":"Vertical rhythm ties text sizing and spacing together"},{"skill":"mobile-ux-optimizer","reason":"Responsive spacing is critical for mobile UX"},{"skill":"motion-design-web","reason":"Spacing affects animation distances and timing"}]}
The definitive reference for layout and spacing in modern web design. Not "use flexbox" — the actual systems, principles, and math behind why good layouts feel right and bad ones feel off.
Spacing is the invisible skeleton of every interface. Color gets the glory, typography gets the respect, but spacing is what makes both of them work. A page with perfect type and color but broken spacing looks amateur. A page with mediocre type but perfect spacing looks professional. That is the power of getting this right.
When to Use
Use for:
Building any web layout from scratch
Establishing spacing tokens for a design system
Debugging layouts that "look wrong" but you cannot articulate why
Converting Figma designs to CSS with accurate spacing
Making responsive layouts that feel right on every screen size
Setting up vertical rhythm for long-form content
Auditing existing sites for spacing inconsistencies
Card layouts, form layouts, dashboard grids, content pages
Do NOT use for:
Animation and motion design (distances yes, timing/easing no) --> use motion-design-web
Typography decisions (font choice, pairing) --> use typography-expert
Full design system architecture --> use design-system-bootstrap
Color and contrast decisions --> use the appropriate color/accessibility skill
Page-level information architecture --> use web-design-expert
The 8px Grid System
The 8px grid is the industry standard for spacing. Apple, Google, and most major design systems use it. The reasons are mathematical: 8 divides cleanly into common screen resolutions (320, 360, 375, 390, 414, 768, 1024, 1280, 1440, 1920), it scales cleanly at 0.75x (6px), 1.5x (12px), and 2x (16px) for device pixel ratios, and it produces spacing values large enough to be visually distinct but small enough to be granular.
The Base Scale
Step Value Tailwind v4 Use Case
─────────────────────────────────────────────────────────
0 0px 0 Reset/collapse
0.5 2px 0.5 Hairline borders, fine adjustments
1 4px 1 Icon padding, tight inline spacing
2 8px 2 Compact element gaps, small padding
3 12px 3 Form field inner padding, list gaps
4 16px 4 Standard component padding, paragraph spacing
5 20px 5 Card inner padding (compact)
6 24px 6 Section sub-gaps, card padding (standard)
8 32px 8 Between related sections, form groups
10 40px 10 Between distinct sections
12 48px 12 Major section spacing
16 64px 16 Page section dividers
20 80px 20 Hero-to-content transition
24 96px 24 Maximum page section spacing
CSS Custom Properties — The Foundation
Every project should define its spacing scale once. Everything else references it.
Use the 4px sub-grid for fine adjustments only — icon-to-label gaps, input padding, borders. If you find yourself using 4px steps everywhere, your elements are too dense.
When NOT to Use 8px Grid
Typography line heights: Line heights follow their own rhythm (see Vertical Rhythm below)
Icon sizes: Icons follow 16/20/24/32 scales, which happen to be 8px-aligned but are driven by optical sizing
Border radius: Radius is aesthetic, not spatial — 4px, 6px, 8px, 12px are all fine
Shadows/blur: Shadow values are perceptual, not grid-based
The Modular Scale
A modular scale generates spacing (and type) values using a base and a ratio: value = base * ratio^n. This produces values that feel harmonically related rather than arbitrarily picked.
Common Ratios and When to Use Each
Ratio Name Feel Best For
──────────────────────────────────────────────────────────
1.125 Major Second Very tight, dense Data-heavy dashboards, admin UIs
1.200 Minor Third Comfortable General purpose, content sites
1.250 Major Third Balanced Blogs, marketing, SaaS
1.333 Perfect Fourth Generous Editorial, luxury brands
1.414 Augmented Fourth Dramatic Portfolio, creative agencies
1.500 Perfect Fifth Very spacious Minimal sites, Apple-style
1.618 Golden Ratio Maximum drama Art, fashion, single-product
This is the most versatile ratio. Here is what the scale produces:
Step Exact Rounded Tailwind Nearest Use Case
────────────────────────────────────────────────────────────────
-3 8.19px 8px 2 Micro gaps
-2 10.24px 10px 2.5 Small icon gaps
-1 12.80px 13px 3 Tight padding
0 16.00px 16px 4 Base unit / body text
1 20.00px 20px 5 H4 / card padding
2 25.00px 25px 6 H3 / section sub-gap
3 31.25px 31px 8 H2 / between groups
4 39.06px 39px 10 H1 / section gap
5 48.83px 49px 12 Page section break
6 61.04px 61px 16 Hero spacing
7 76.29px 76px 20 Maximum spacing
Grid vs. Modular Scale — When to Use Which
Use the 8px grid when:
Building a design system used by many designers/developers
Consistency across a large product is paramount
Working with a team that needs simple, predictable values
Building data-dense applications (dashboards, admin panels)
Use a modular scale when:
Building a marketing site or editorial product
You want a distinctive visual rhythm
Typography is a primary design element
Working solo or with a small team that groks the math
In practice, use both: The 8px grid for layout structure, the modular scale for typography and content spacing. Snap modular scale outputs to the nearest 4px value for the best of both worlds.
Vertical Rhythm
Vertical rhythm means all vertical spacing in your layout aligns to a baseline grid. Text, images, padding, margins — everything snaps to multiples of a single line-height unit. This creates the invisible order that makes professional layouts feel "right."
The lh unit equals the computed line-height of the current element. The rlh unit equals the computed line-height of the root element (<html>). These are purpose-built for vertical rhythm and have 94%+ browser support (shipped in all browsers by end of 2023).
html {
font-size: 16px;
line-height: 1.5; /* 1rlh = 24px */
}
/* Spacing that inherently follows vertical rhythm */
article p {
margin-bottom: 1lh; /* One line of spacing */
}
article h2 {
margin-top: 2rlh; /* Two root-level lines above */
margin-bottom: 0.5rlh; /* Half a root-level line below */
}
article blockquote {
padding: 1lh 1.5rem; /* Vertical padding = one line */
margin: 1.5lh 0; /* Vertical margin = 1.5 lines */
}
/* Progressive enhancement for older browsers */
article p {
margin-bottom: 1.5rem; /* Fallback */
margin-bottom: 1lh; /* Modern browsers */
}
When to use lh vs rlh:
lh — Component-level spacing that scales with local font size (cards, form fields, article body)
rlh — Site-wide structural spacing that stays consistent regardless of local font size (page sections, nav, sidebar)
Debugging Vertical Rhythm
Add a visual baseline grid overlay to check alignment:
/* Development only — toggle with a class */
.show-baseline {
background-image: linear-gradient(
to bottom,
transparent calc(1rlh - 1px),
rgba(0, 150, 255, 0.15) calc(1rlh - 1px),
rgba(0, 150, 255, 0.15) 1rlh
);
background-size: 100% 1rlh;
}
Layout Primitives — The "Every Layout" System
Heydon Pickering and Andy Bell identified that all web layouts are compositions of a small number of primitives. Each is intrinsically responsive — no media queries needed. Together they replace thousands of lines of bespoke layout CSS.
1. The Stack
Injects consistent vertical space between sibling elements. The single most important layout primitive.
Use for: Page content containers, article bodies, any centered column of content.
4. The Sidebar
A two-panel layout where one panel has a fixed (or content-driven) width and the other fills remaining space. Stacks vertically when the container is too narrow.
When the container is wider than --threshold, children sit side by side (flex-basis becomes a large negative number, so flex-grow takes over). When narrower, flex-basis becomes a large positive number, forcing wrap.
Use for: Feature comparison grids, pricing cards, any N-up layout that should stack on mobile.
6. The Cover
A full-height layout (usually viewport height) with a centered principal element and optional header/footer.
One-dimensional flow — a row of buttons, a column of nav items
Content-driven sizing — items sized by their content, not the grid
Wrapping groups — clusters, tag lists, breadcrumbs
Single-axis alignment — centering one thing in a container
Unknown item count — "however many items there are, space them evenly"
/* Navigation — always Flexbox */
.nav {
display: flex;
align-items: center;
gap: var(--space-4);
}
.nav-links {
display: flex;
gap: var(--space-6);
margin-inline-start: auto; /* Push to the right */
}
Use Subgrid For:
Subgrid (97%+ browser support, Chrome 117+, Firefox 71+, Safari 16+) lets nested elements align to their parent grid's tracks. This solves the "card content alignment" problem that plagued CSS for years.
.card-grid {
display: grid;
grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
gap: var(--space-6);
}
.card {
display: grid;
grid-template-rows: subgrid;
grid-row: span 3; /* Card spans 3 parent rows: image, content, actions */
}
/* Now every card's image, content, and action bar align across the row */
The Decision Tree
Need to place items in ROWS and COLUMNS?
├── YES → CSS Grid
│ ├── Children need to align with grandparent grid? → Subgrid
│ └── Layout known ahead of time? → Named grid areas
└── NO → One dimension only
├── Items should wrap? → Flexbox + flex-wrap
├── Items should scroll? → Flexbox + overflow-x (Reel)
└── Items in a line? → Flexbox
Fluid Spacing with clamp()
Hard breakpoints create jarring spacing jumps. Fluid spacing scales smoothly between a minimum and maximum value based on viewport (or container) width.
For dramatic spacing jumps (e.g., mobile section gap = 24px, desktop = 64px), skip scale steps:
:root {
/* "s-l" pair: small on mobile, large on desktop */
--fluid-space-s-l: clamp(0.5rem, -0.07rem + 2.86vw, 3rem); /* 8px → 48px */
/* "m-xl" pair: medium on mobile, extra-large on desktop */
--fluid-space-m-xl: clamp(1rem, 0.14rem + 4.29vw, 4rem); /* 16px → 64px */
}
These are ideal for section spacing where mobile needs tighter gaps but desktop can breathe.
Container Query Units for Component Spacing
When a component needs to adapt its spacing to its container (not the viewport), use container query units. Full browser support as of 2025.
.card-container {
container-type: inline-size;
container-name: card;
}
.card {
/* Spacing scales with the card's container, not the viewport */
padding: clamp(0.75rem, 3cqi, 2rem);
gap: clamp(0.5rem, 2cqi, 1.5rem);
}
/* When the container is wide enough, switch layout */
@container card (min-inline-size: 400px) {
.card {
display: grid;
grid-template-columns: 200px 1fr;
gap: var(--space-6);
}
}
Container query unit reference:
cqw — 1% of the query container's width
cqh — 1% of the query container's height
cqi — 1% of the query container's inline size (preferred for international support)
cqb — 1% of the query container's block size
cqmin — smaller of cqi or cqb
cqmax — larger of cqi or cqb
Whitespace as a Design Element
Whitespace is not empty space — it is active design material. The amount of whitespace directly communicates hierarchy, grouping, and importance. Increasing whitespace by 50% can boost comprehension by 20%.
Micro vs. Macro Whitespace
Micro whitespace — the space within and between small elements:
Letter spacing (tracking)
Line height (leading)
Padding inside buttons, inputs, chips
Gap between icon and label
Space between list items
Macro whitespace — the space between large sections:
Where you sit on this spectrum should be a deliberate choice, not an accident:
Dense (4px base) — Dashboards, trading platforms, IDE-like interfaces. Every pixel matters. Users are experts who want maximum information density.
Comfortable (8px base) — SaaS products, productivity tools. Balance between information and breathing room.
Spacious (12-16px base) — Marketing sites, portfolios, editorial. Whitespace IS the design. Each element has room to breathe and be appreciated.
How Apple Uses Whitespace
Apple uses whitespace aggressively. Typical patterns:
Hero sections with 120-200px top/bottom padding
Product images floating in vast empty space (60-70% of the viewport is white)
Text blocks constrained to 580-650px wide, centered in full-width sections
Section-to-section gaps of 100-160px
Minimal navigation (small logo, few links, lots of space between them)
How Stripe Uses Whitespace
Stripe balances information density with elegance:
Content max-width of ~1080px, centered with generous side padding
Section padding of 80-120px top/bottom
Card components with 32-48px internal padding
Code blocks with 24px padding, 16px gap between code and description
Feature grids with 32-48px gap between items
How Linear Uses Whitespace
Linear epitomizes the modern SaaS aesthetic:
Full-bleed sections with 80-100px padding
Feature descriptions with 48-64px between heading and body
Screenshots/demos floating in dark backgrounds with 40-60px padding
Compact navigation with precisely 24px between items
Modular sections that each feel like a complete "slide"
Component-Level Spacing
The Padding Ratio for Interactive Elements
Buttons, inputs, pills, and chips follow a consistent ratio: vertical padding is roughly 60-66% of horizontal padding. This is close to the golden ratio (0.618) and accounts for how the human eye perceives horizontal vs. vertical space differently.
/* Button padding ratios */
.btn-sm {
padding: 6px 12px; /* 0.50 ratio — compact */
/* Or: padding: 0.375rem 0.75rem; */
}
.btn-md {
padding: 10px 16px; /* 0.625 ratio — standard, near golden */
/* Or: padding: 0.625rem 1rem; */
}
.btn-lg {
padding: 14px 24px; /* 0.583 ratio — generous */
/* Or: padding: 0.875rem 1.5rem; */
}
.btn-xl {
padding: 18px 32px; /* 0.5625 ratio — hero CTA */
/* Or: padding: 1.125rem 2rem; */
}
/* Input fields follow the same principle */
.input {
padding: 10px 14px; /* Slightly more horizontal than buttons */
}
/* Pills / chips — tighter ratio because they are small */
.pill {
padding: 4px 10px; /* 0.4 ratio */
}
Gap as First-Class Spacing
In modern CSS, gap has replaced margin for spacing between siblings inside flex and grid containers. Always prefer gap over margins for sibling spacing.
/* OLD — margin-based (fragile, causes collapse issues) */
.old-list > * + * {
margin-top: 1rem;
}
/* NEW — gap-based (clean, no collapse, works in flex and grid) */
.new-list {
display: flex;
flex-direction: column;
gap: 1rem;
}
Why gap wins:
No margin collapse issues
Works identically in Flexbox and Grid
Single property controls both row-gap and column-gap
Does not add space before the first or after the last item
Easier to override with a single custom property
Card Spacing System
Cards are the most common component in web design. Their spacing needs a system:
A foundational spacing rule from Gestalt psychology: space inside a component should be less than or equal to space outside it. This creates clear visual boundaries without needing borders or backgrounds.
When the external gap is generous relative to internal padding, each card reads as its own entity. When internal padding exceeds external gap, cards blur together into an amorphous mass.
Page-Level Composition
Max-Width Containers
Why is 1200px the most common max-width? It is not magic — it is the comfortable reading width at standard text sizes on the most common desktop resolution (1440px or 1920px). At 1200px max-width on a 1440px screen, you get 120px of side breathing room. On 1920px, you get 360px — generous but not wasteful.
/* Standard content container */
.container {
width: 100%;
max-width: 75rem; /* 1200px */
margin-inline: auto;
padding-inline: var(--gutter, 1.5rem);
}
/* Narrow for long-form reading (optimal: 45-75 characters per line) */
.container-prose {
max-width: 42rem; /* ~672px ≈ 65ch at 16px body text */
}
/* Wide for dashboards and data-heavy pages */
.container-wide {
max-width: 90rem; /* 1440px */
}
/* Full-bleed for hero sections and backgrounds */
.container-full {
max-width: none;
padding-inline: 0;
}
Common Max-Width Values and Their Use Cases
Width rem Use Case Example Sites
──────────────────────────────────────────────────────────────────────
640px 40rem Narrow prose, centered forms Medium articles
768px 48rem Blog content, documentation MDN, Notion pages
960px 60rem Balanced content + whitespace GitHub READMEs
1080px 67.5rem Marketing content sections Stripe, Linear
1200px 75rem Standard page container Most SaaS products
1440px 90rem Wide dashboards, admin panels Vercel Dashboard
100% 100% Full-bleed backgrounds/heroes Apple product pages
Gutter Calculations
Gutters are the space between the edge of the viewport and your content container. They should be fluid:
A common pattern: the main content is constrained to 1200px, but some sections (hero, testimonial bands, CTA strips) stretch full-width with colored backgrounds.
Unit Meaning Use When
────────────────────────────────────────────────────────────
vh 1% of viewport height Legacy fallback only
vw 1% of viewport width Fluid calculations
dvh 1% of dynamic viewport Mobile-safe full-height (changes with browser chrome)
svh 1% of small viewport Conservative: assumes browser chrome IS showing
lvh 1% of large viewport Generous: assumes browser chrome is NOT showing
For mobile-safe full-height layouts, always use dvh:
.hero {
min-height: 100vh; /* Fallback */
min-height: 100dvh; /* Modern: accounts for mobile browser chrome */
}
When to Use Breakpoints vs. Fluid Scaling
Use fluid scaling (clamp) for:
Font sizes
Padding and margins that should grow/shrink smoothly
Container gutters
Section spacing
Use breakpoints for:
Layout structure changes (1 column → 2 columns)
Showing/hiding elements (mobile menu vs. desktop nav)
Token Value Use
─────────────────────────────────────────
$spacing-01 2px Fine adjustments
$spacing-02 4px Compact padding
$spacing-03 8px Small gaps
$spacing-04 12px Form spacing
$spacing-05 16px Standard spacing
$spacing-06 24px Component groups
$spacing-07 32px Section gaps
$spacing-08 40px Large sections
$spacing-09 48px Page sections
$spacing-10 64px Major divisions
$spacing-11 80px Page-level
$spacing-12 96px Maximum
$spacing-13 160px Hero spacing
Atlassian Design System
Semantic naming with 8px base:
Token Value Description
──────────────────────────────────────────────────
space.0 0px Zero
space.025 2px Hairline
space.050 4px Tightest
space.075 6px Tighter
space.100 8px Tight
space.150 12px Compact
space.200 16px Normal (default)
space.250 20px Comfortable
space.300 24px Spacious
space.400 32px Very spacious
space.500 40px Extra spacious
space.600 48px Section-level
space.800 64px Page-level
space.1000 80px Maximum
Common Spacing Mistakes
Mistake 1: Inconsistent Values
/* BAD — 8 different "small" gaps. Which is the right one? */
.header { gap: 10px; }
.nav { gap: 12px; }
.sidebar { gap: 11px; }
.card { gap: 14px; }
.form { gap: 13px; }
.footer { gap: 9px; }
.modal { gap: 15px; }
.dropdown { gap: 8px; }
/* GOOD — one token, one value, used everywhere */
.header,
.nav,
.sidebar,
.card,
.form,
.footer,
.modal,
.dropdown {
gap: var(--space-3); /* 12px — the one true "small gap" */
}
Fix: Audit your CSS for unique spacing values. A well-designed system uses 8-12 distinct values. If you have 30+, you have a problem.
Mistake 2: Margin Collapse Surprises
Margin collapse happens when vertical margins of adjacent block elements combine into one margin (the larger wins). This only affects block layout — it does NOT happen in Flexbox or Grid.
/* GOTCHA: These margins collapse — you get 32px, not 56px */
.heading { margin-bottom: 24px; }
.paragraph { margin-top: 32px; }
/* Actual gap: 32px (the larger margin wins) */
/* GOTCHA: Parent-child collapse */
.parent { margin-top: 0; }
.child { margin-top: 24px; }
/* The child's margin "escapes" and pushes the PARENT down by 24px */
/* FIX 1: Use gap (no collapse in flex/grid) */
.container {
display: flex;
flex-direction: column;
gap: 24px;
}
/* FIX 2: Use padding on the parent to block parent-child collapse */
.parent { padding-top: 1px; } /* Even 1px blocks collapse */
/* FIX 3: Use overflow to create a block formatting context */
.parent { overflow: hidden; }
/* FIX 4: Use margin in only one direction (Heydon Pickering's "lobotomized owl") */
* + * { margin-top: 1.5rem; } /* Only top margins, no collapse risk */
Mistake 3: Desktop-First Spacing That Breaks on Mobile
/* BAD — 96px section padding looks great on desktop, absurd on 375px mobile */
section {
padding: 96px 48px;
}
/* GOOD — fluid spacing that adapts */
section {
padding: clamp(2rem, 4vw + 1rem, 6rem) var(--gutter);
}
Mistake 4: Over-Spacing That Wastes Real Estate
Not everything needs 80px of breathing room. Over-spacing pushes content below the fold, increases scroll depth, and can make pages feel empty rather than elegant.
/* BAD — every element drowning in whitespace */
h2 { margin-top: 80px; margin-bottom: 40px; }
p { margin-bottom: 32px; }
ul { margin-bottom: 48px; }
/* User scrolls forever to reach the CTA */
/* GOOD — proportional to content importance */
h2 { margin-top: 48px; margin-bottom: 16px; }
p { margin-bottom: 16px; }
ul { margin-bottom: 24px; }
Mistake 5: Using Padding When You Mean Margin (or Vice Versa)
PADDING = space INSIDE the element boundary (between border and content)
MARGIN = space OUTSIDE the element boundary (between element and neighbors)
Use PADDING for:
- Internal breathing room (card content inset)
- Click/tap target expansion
- Background color coverage area
Use MARGIN for:
- Separation between distinct elements
- Push away from siblings
- Page-level section spacing (or use gap)
Use GAP for:
- Space between children of a flex/grid container
- ALWAYS prefer gap over margin for sibling spacing
Mistake 6: Ignoring the 4px Sub-Grid for Small Elements
/* BAD — 8px gap between icon and label feels too wide */
.icon-label { gap: 8px; }
/* GOOD — drop to the 4px sub-grid for tight pairings */
.icon-label { gap: 4px; }
/* Also good for: */
.badge { padding: 2px 6px; } /* 2px top/bottom, 6px sides */
.avatar-sm { width: 24px; height: 24px; }
.divider { margin-block: 4px; }
Debugging "Why Does This Look Wrong?"
The Squint Test
Literally squint at your screen (or step back 5 feet). When you cannot read the text, your brain sees only shapes and spacing. Ask:
Do elements group naturally? (Related items should cluster)
Are there clear visual sections? (Macro whitespace should separate groups)
Does anything float awkwardly? (Orphaned elements not clearly belonging to a group)
Is the page balanced? (No side feels heavier than the other)
The Color Block Test
Temporarily add colored backgrounds to all your containers:
All modern browsers show margin/padding visually when you inspect an element:
Margin — shown in orange/amber
Padding — shown in green
Content — shown in blue
Border — shown in yellow/gold
In Chrome DevTools, hover over any element to see its box model visualization overlaid on the page. In Firefox, the Layout tab shows grid and flex overlays with detailed gap visualization.
Target: 8-15 unique values for a well-designed system. If you see 30+, your spacing is ad-hoc and needs a system.
Common Visual Problems and Their Fixes
SYMPTOM LIKELY CAUSE FIX
─────────────────────────────────────────────────────────────────────────────
Elements look "merged together" Internal >= external spacing Increase gap, decrease padding
One section feels "detached" Too much margin above/below Reduce to match siblings
Cards don't align across rows No shared grid tracks Use CSS Grid + subgrid
Text feels cramped Line-height < 1.4 Set line-height: 1.5-1.6
Text feels too airy Line-height > 1.8 Bring down to 1.5-1.6
Page feels "empty" Over-spacing (macro) Tighten section padding
Page feels "cluttered" Under-spacing, no hierarchy Add macro whitespace between groups
Button text feels off-center Unequal optical padding Add 1-2px more to top (caps sit high)
Sidebar and main don't feel related Gutter too wide Reduce to 24-32px
Hero → content transition is jarring Abrupt spacing change Use fluid spacing for section padding
Anti-Patterns
"Magic number" spacing — Pixel values scattered through CSS with no tokens or scale. Every spacing value should reference a token or scale step.
Spacing with invisible elements — Using empty divs or <br> tags for spacing instead of proper margin/padding/gap. Never use markup for presentation.
Percentage padding for vertical space — padding: 10% computes based on the element's WIDTH, not height. This almost never does what you expect for vertical spacing.
Fixed spacing at every breakpoint — Writing padding: 16px then @media (min-width: 768px) { padding: 24px } then @media (min-width: 1024px) { padding: 32px } when clamp(1rem, 2vw + 0.5rem, 2rem) handles all three.
Mixing margin directions — Some elements push with margin-bottom, others with margin-top, some with both. Pick ONE direction (margin-bottom is conventional) and stick with it, or use gap exclusively.
Ignoring the content measure — Lines of text wider than 75 characters are hard to read. Always constrain prose containers to 45-75ch (roughly 38-65rem at 16px body text).
Copying spacing from Figma 1:1 without fluid adaptation — Figma designs are fixed-width. Translating them to CSS without adding fluid scaling produces layouts that only look right at one viewport width.
Using margin on flex/grid children for sibling spacing — Use gap on the parent instead. Margin on children creates maintenance headaches and edge cases (first/last child exceptions).
Spacing tokens that are too granular — 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 pixel tokens. Nobody can distinguish 7px from 8px. Remove values that are not optically distinct (minimum 4px step between tokens).
No spacing documentation — If your design system does not have a published spacing scale with names, values, and usage guidelines, every developer will invent their own spacing, and they will all be different.
Quality Checklist
Before shipping any layout:
Spacing scale defined — All spacing values reference tokens from a defined scale (8-15 unique values max)
8px grid alignment — All major spacing values are multiples of 8px (4px for fine adjustments)
Vertical rhythm — Line heights and vertical margins align to a baseline grid
Internal < external — Component padding is less than or equal to the gap between components
Fluid spacing — Section padding and major gaps use clamp() for smooth scaling
Container max-width — Prose content constrained to 45-75ch, page content to 1200px (or justified wider)
Mobile tested — Spacing is not absurdly tight or absurdly generous on 375px viewport
Desktop tested — Layout does not feel empty or over-spaced on 1440px+ viewport
Squint test passed — Visual hierarchy is clear when you squint at the page
Margin direction consistent — Margins go in one direction, or you use gap exclusively
No magic numbers — No raw pixel values in CSS; everything uses tokens or calc with tokens
Gutter symmetry — Left and right page gutters are equal and fluid
Interactive target sizes — Buttons and links have at least 44x44px tap target (including padding)
Subgrid for card alignment — Card grids use subgrid so headings, content, and CTAs align across rows
DevTools audit — Spacing overlay shows no unexpected gaps, overlaps, or collapse artifacts
