Lily Design System™

Content Block

A content width constraint container with named column widths. ContentBlock constrains child content to a named column width, reading CSS custom properties set by an ArticleLayout parent.

This headless component uses a <div> element as a presentational container with no ARIA semantics.

Example

ContentBlock
Show demo markup 
<div class="content-block" aria-label="a content width constraint container with named column widths">ContentBlock</div>
Usage example 
<ContentBlock width="narrow">
  <p>Narrow column text content.</p>
</ContentBlock>
<ContentBlock width="wide">
  <img src="chart.png" alt="Data visualization" />
</ContentBlock>
Show Svelte source 
// In your Svelte component:
import ContentBlock from "lily-design-system-svelte-headless/components/ContentBlock/ContentBlock.svelte";

<ContentBlock>
  <!-- content -->
</ContentBlock>

Usage

<ContentBlock width="narrow">
  <p>Narrow column text content.</p>
</ContentBlock>
<ContentBlock width="wide">
  <img src="chart.png" alt="Data visualization" />
</ContentBlock>
<ArticleLayout>
  <ContentBlock width="narrower">
    <p>Very narrow sidebar content.</p>
  </ContentBlock>
  <ContentBlock>
    <p>Default normal-width body text.</p>
  </ContentBlock>
  <ContentBlock width="wider">
    <figure>
      <img src="panorama.jpg" alt="Landscape panorama" />
      <figcaption>A wide landscape image.</figcaption>
    </figure>
  </ContentBlock>
  <ContentBlock width="fluid">
    <div>Full-width content.</div>
  </ContentBlock>
</ArticleLayout>

Props

  • width: "narrower" | "narrow" | "normal" | "wide" | "wider" | "widest" | "fluid" (default: "normal") -- content width
  • children: slot (required) -- block content
  • ...restProps: Any additional HTML attributes

Keyboard Interactions

  • None

ARIA

  • None -- presentational container

When to Use

  • Use inside ArticleLayout to constrain content to specific column widths
  • Use when different content blocks need different widths on the same page
  • Use for editorial layouts where text, images, and charts have different optimal widths

When Not to Use

  • Do not use outside of article or editorial layouts
  • Do not use for application-level layout constraints -- use GrailLayout instead

Headless

This component provides a <div> element with a data-width attribute, with zero visual styling. The consumer is responsible for all CSS including max-width, margins, padding, and responsive behavior.

Styles

The consumer provides all CSS styling. The component renders with a .content-block class and a data-width attribute for targeting. No default styles are included -- this is a fully headless component.

Testing

  • Verify the component renders a <div> element with class content-block
  • Verify data-width attribute reflects the width prop
  • Verify default width is "normal" when no width prop is provided
  • Verify child content slots are rendered correctly
  • Verify pass-through attributes are applied

Advice

  • Designers: Use narrower widths (330px--510px) for body text to maintain optimal line length. Use wider widths for images, charts, and data visualizations.
  • Developers: The data-width attribute allows CSS targeting for each width variant. Use CSS custom properties from the parent ArticleLayout to control actual widths.

Implementation Notes

  • Constrains child content to a named column width
  • Reads CSS custom properties set by ArticleLayout parent
  • data-width attribute reflects the current width for CSS targeting
  • Centers content horizontally with auto margins
  • Inspired by Reuters Graphics Block component

Related components

  • container — a generic block-level content container
  • container-with-fluid-width — a full-width content wrapper with horizontal padding

References

  • Reuters Graphics Block component
  • Documentation: index.md
  • CSS class: .content-block in css-style-sheet-template.css
  • HTML headless: lily-design-system-html-headless/components/content-block.html

Canonical contract

Generated from this component's canonical metadata — the machine-checked source the implementations are held to.

Metadata

  • Component: content-block
  • PascalCase: ContentBlock
  • Description: a content width constraint container with named column widths
  • Status: beta — implemented and unit-tested in all seven frameworks with an axe-clean demo page; not yet exercised in composed flows
  • HTML tag: <div>
  • CSS class: .content-block
  • Interactive: no

ARIA

  • None -- presentational container

Keyboard

  • None

Props

  • width: "narrower" | "narrow" | "normal" | "wide" | "wider" | "widest" | "fluid" (default: "normal") -- content width
  • children: slot (required) -- block content
  • ...restProps: Any additional HTML attributes