Understanding CSS Architecture: Part 3 - Modern Features
Modern CSS features are revolutionizing how we architect stylesheets. Features that previously required JavaScript or complex workarounds are now native to CSS.
Container Queries#
Container queries let components respond to their container's size, not just the viewport:
.card-container {
container-type: inline-size;
container-name: card;
}
.card {
display: grid;
gap: var(--space-sm);
}
/* When container is wide enough */
@container card (min-width: 400px) {
.card {
grid-template-columns: 200px 1fr;
}
}
@container card (min-width: 600px) {
.card {
grid-template-columns: 300px 1fr;
gap: var(--space-lg);
}
}
This enables truly reusable components that adapt to any context.
The :has() Selector#
The :has() selector (parent selector) unlocks new patterns:
/* Style card differently when it has an image */
.card:has(img) {
padding-top: 0;
}
/* Style form groups with invalid inputs */
.form-group:has(:invalid) {
--input-border: var(--color-error);
}
/* Adjust layout when sidebar is present */
.layout:has(.sidebar) {
grid-template-columns: 250px 1fr;
}
/* Style label when checkbox is checked */
label:has(input:checked) {
font-weight: bold;
}
CSS Nesting#
Native CSS nesting reduces repetition:
.card {
padding: var(--space-md);
background: var(--color-surface);
& .title {
font-size: var(--text-lg);
font-weight: bold;
}
& .body {
color: var(--color-muted);
}
&:hover {
box-shadow: var(--shadow-lg);
}
@media (min-width: 768px) {
padding: var(--space-lg);
}
}
Cascade Layers#
Layers give explicit control over cascade priority:
@layer reset, base, components, utilities;
@layer reset {
* { margin: 0; }
}
@layer base {
a { color: var(--color-link); }
}
@layer components {
.btn { /* ... */ }
}
@layer utilities {
.hidden { display: none; }
}
Layer order in the @layer statement determines priority—later layers override earlier ones.
Logical Properties#
Write direction-agnostic styles:
/* Old way - direction-specific */
.card {
margin-left: 1rem;
margin-right: 1rem;
padding-top: 2rem;
padding-bottom: 2rem;
}
/* New way - logical properties */
.card {
margin-inline: 1rem;
padding-block: 2rem;
}
This improves internationalization support automatically.
Subgrid#
Align nested grids to parent tracks:
.grid {
display: grid;
grid-template-columns: repeat(3, 1fr);
gap: var(--space-md);
}
.grid-item {
display: grid;
grid-template-rows: subgrid;
grid-row: span 3;
}
Architectural Implications#
These features change how we architect CSS:
- Fewer wrapper divs -
:has()and container queries reduce structural markup - More encapsulated components - Container queries make components truly portable
- Simpler specificity - Layers give explicit cascade control
- Less JavaScript - Many interactions now possible in pure CSS
Browser Support#
Check browser support before using:
- Container Queries: All modern browsers
:has(): All modern browsers- Nesting: All modern browsers
- Cascade Layers: All modern browsers
Conclusion#
Modern CSS features enable simpler, more maintainable architectures. Embrace these features to write less code that does more.
This concludes our CSS Architecture series. Happy styling!
