Layout Extras (`layouts/layout-extra.css`)

This supplementary file extends the core layout system with mixins, functions, and utility classes. It provides both CSS-centric approaches for applying layout

.search-layout {
  @apply --layout-sidebar(
    --sidebar-width: 16rem,
    --gap: var(--space-lg)
  );
}

.search-layout {
  @apply --layout-sidebar(
    --sidebar-width: 16rem,
    --main-min-width: 24rem,
    --gap: var(--space-lg)
  );
}

This supplementary file extends the core layout system with mixins, functions, and utility classes. It provides both CSS-centric approaches for applying layout patterns and utilities for enhancing layout components.

Overview

The file contains three main sections:

1. Layout Mixins: Proposed CSS mixins for applying layout logic to any element
2. Layout Functions: Proposed CSS functions for common calculations
3. Utility Classes: Ready-to-use classes for shadows, positioning, and layout effects

Important Notice

⚠️ Proposed Features: The @mixin and @function rules demonstrated here are not supported in any browser as of late 2025. This file showcases a forward-looking, preprocessor-free approach for future CSS standards.

Layout Mixins (Proposed)

These mixins allow applying layout component logic directly to standard HTML elements.

@mixin --layout-stack

Applies vertical stacking logic to any element.

Parameters:

• --gap: Space between stacked items (default: var(--space-md, 1.5rem))
• --align: Horizontal alignment of items (default: stretch)

Example Usage:

.product-details {
  @apply --layout-stack(--gap: 2rem, --align: flex-start);
}

Generated Styles:

display: flex;
flex-direction: column;
justify-content: flex-start;
align-items: var(--align);
gap: var(--gap, var(--space-md, 1.5rem));

@mixin --layout-grid

Applies responsive grid logic to any element.

Parameters:

• --min-item-size: Minimum size for each grid item (default: 16rem)
• --gap: Gap between items (default: var(--space-md, 1.5rem))

Example Usage:

.card-collection {
  @apply --layout-grid(--min-item-size: 20rem);
}

Generated Styles:

display: grid;
gap: var(--gap, var(--space-md, 1.5rem));
grid-template-columns: repeat(auto-fit, minmax(min(100%, var(--min-item-size, 16rem)), 1fr));

@mixin --layout-sidebar

Applies responsive sidebar layout logic.

Parameters:

• --side-width: Width of the sidebar (default: 20rem)
• --content-min: Minimum width for main content before wrapping (default: 50%)
• --gap: Space between sidebar and content (default: var(--space-lg, 2rem))

Example Usage:

main.with-sidebar {
  @apply --layout-sidebar(--side-width: 250px);

  & > :last-child {
    flex-basis: var(--side-width); /* Match sidebar width */
  }
}

Generated Styles:

display: flex;
flex-wrap: wrap;
gap: var(--gap, var(--space-lg, 2rem));

& > :first-child { /* Main content */
  flex-grow: 9999;
  flex-basis: var(--content-min, 50%);
}
& > :last-child { /* Sidebar */
  flex-grow: 1;
  flex-basis: var(--side-width, 20rem);
}

Layout Functions (Proposed)

@function --aspect-ratio

Returns a clean aspect-ratio value for CSS.

Parameters:

• --width: Width component of the ratio (number)
• --height: Height component of the ratio (number)

Returns: String in format “width / height”

Example Usage:

.video-player {
  aspect-ratio: --aspect-ratio(16, 9);
}

Result: aspect-ratio: 16 / 9;

Utility Classes

These classes can be applied to layout components or any elements for common effects.

Shadow Utilities

Apply consistent, token-based shadows using predefined shadow tokens.

Available Classes:

• .has-shadow-sm: Small shadow
• .has-shadow-md: Medium shadow
• .has-shadow-lg: Large shadow

CSS Properties Used:

• --shadow-1: Small shadow (default: 0 1px 3px rgb(0 0 0 / 0.1))
• --shadow-2: Medium shadow (default: 0 4px 6px rgb(0 0 0 / 0.1))
• --shadow-3: Large shadow (default: 0 10px 15px rgb(0 0 0 / 0.1))

Example:

<layout-sidebar class="has-shadow-md">
  <main>Content</main>
  <aside>Sidebar</aside>
</layout-sidebar>

.is-sticky

Makes an element stick to the top of its scrolling container. Perfect for sidebars or headers.

CSS Properties:

• --sticky-top-offset: Offset from top (default: 1rem)

Features:

• position: sticky
• align-self: start to prevent stretching in flex/grid
• max-height calculation to prevent overflow
• overflow-y: auto for scrollable content

Example:

<layout-sidebar>
  <main>Main content</main>
  <aside class="is-sticky">Sticky sidebar</aside>
</layout-sidebar>

.is-full-bleed

Allows a child element to break out of its parent container’s padding and stretch to the full viewport width.

Implementation:

• width: 100vw
• margin-inline: 50%
• transform: translateX(-50%)

Example:

<layout-center>
  <p>Constrained text</p>
  <img src="hero.jpg" alt="Hero" class="is-full-bleed">
  <p>More constrained text</p>
</layout-center>

Browser Support

• Utility classes work in all modern browsers
• Mixins and functions are proposed features not yet implemented
• Shadow utilities depend on shadow tokens defined in core/base.css

Integration Notes

• Utility classes can be combined with layout components
• Shadow tokens should be defined in global stylesheets
• Mixins/functions represent future CSS capabilities
• Import this file after core layout components in index.css

Related Files

• layouts/layout.css: Core layout components
• core/base.css: Defines shadow and spacing tokens
• core/theme.css: Theme-specific shadow overrides