Using Styling The Details Element

Master native expandable content with modern CSS techniques for accessible, JavaScript-free accordions

Why Use the Details Element

The <details> element provides built-in accessibility, works without JavaScript, and delivers a consistent user experience across all modern browsers. It's the recommended solution for FAQ sections, expandable descriptions, and content that benefits from progressive disclosure.

Key Benefits

The details element eliminates the need for custom JavaScript implementations, reducing development time and maintenance overhead. It provides native keyboard navigation and screen reader support out of the box. The element's semantics are understood by search engines, which can improve content indexing. Additionally, the closed state reduces visual clutter, improving page readability and user engagement.

Common Use Cases

FAQ sections remain the most popular application, allowing users to expand answers to common questions without scrolling through lengthy content. Product detail pages often use details elements for specifications, sizing guides, and shipping information that users may or may not need. Documentation sites leverage expandable sections for table of contents, code examples, and detailed explanations. Content management interfaces frequently employ details elements for collapsible panels and settings sections.

For teams implementing AI-powered interfaces, the details element provides an accessible way to hide complex outputs until users want to see them, keeping the interface clean while maintaining full functionality. This pattern integrates seamlessly with our AI integration services for building intelligent web applications.

Basic HTML Structure
1<details>2 <summary>Click to expand</summary>3 <p>This content is hidden until the widget is opened.</p>4 <p>You can include any HTML elements here.</p>5</details>
Key Benefits of the Details Element

No JavaScript Required

Native expandable functionality without any scripting, reducing code complexity and maintenance.

Built-in Accessibility

Automatic keyboard navigation and screen reader support for all users.

SEO Friendly

Semantic markup that search engines understand and index properly.

Cross-Browser Support

Works consistently across all modern browsers with no polyfills needed.

The Name Attribute for Exclusive Accordions

Modern browsers support the name attribute on <details> elements, enabling exclusive accordion behavior without JavaScript. When multiple <details> elements share the same name value, only one can be open at a time. Opening one automatically closes others in the same group.

This feature works across all major browsers and eliminates the JavaScript typically required for accordion functionality, as documented by Chrome for Developers. For web development teams, this means simpler codebases with fewer dependencies and potential points of failure. Combined with our web development services, this approach helps build faster, more maintainable websites.

Exclusive Accordion with Name Attribute
1<details name="accordion">2 <summary>Section 1</summary>3 <p>Content for section 1.</p>4</details>5 6<details name="accordion">7 <summary>Section 2</summary>8 <p>Content for section 2.</p>9</details>10 11<details name="accordion">12 <summary>Section 3</summary>13 <p>Content for section 3.</p>14</details>

Modern CSS Styling Capabilities

Recent browser updates have dramatically expanded the styling possibilities for <details> and <summary> elements. Chrome 131 introduced the ability to set display properties on these elements, opening new layout possibilities.

Display Property Support

Previously, setting display: flex or display: grid on <details> elements was not supported. This restriction has been relaxed, enabling developers to create horizontal accordions, side-by-side layouts, and more sophisticated arrangements, as covered in Chrome's styling documentation.

The ::details-content Pseudo-Element

Chrome 131 introduced the ::details-content pseudo-element, which targets the expandable content area separately from the summary. This allows for independent styling of the content container, including background colors, padding, and transitions, as documented on MDN.

Horizontal Accordion with Flexbox
1details {2 display: flex;3 flex-direction: row;4}5 6details[open] summary {7 border-bottom: 1px solid #ddd;8}

Custom Marker Styling

The default disclosure marker varies by browser but typically appears as a triangle. Modern CSS provides several approaches to customize or replace this marker entirely.

Hiding the Default Marker

The default marker can be hidden using the list-style property or by removing it from the marker pseudo-element. This approach removes the browser-provided indicator entirely, allowing for complete custom marker implementation.

Custom Markers with ::before or ::after

After hiding the default marker, you can add custom indicators using pseudo-elements. This technique works reliably across all modern browsers and allows complete control over marker appearance, including using custom icons, images, or Unicode characters.

Rotating Marker Animation

For a more polished interactive feel, the marker can rotate when the widget opens using CSS transitions.

Custom Rotating Marker
1summary {2 list-style: none;3 position: relative;4 padding-left: 1.5rem;5 cursor: pointer;6}7 8summary::before {9 content: "▶";10 position: absolute;11 left: 0;12 transition: transform 0.2s ease;13}14 15details[open] summary::before {16 transform: rotate(90deg);17}

Animation Techniques

Animating <details> elements has historically been challenging because the element cannot animate height changes natively. Several techniques have emerged to create smooth open and close transitions.

Height Transition Workaround

The most common approach involves animating the max-height property, though this requires knowing or estimating the maximum content height.

Grid Layout Animation

A more robust approach uses CSS Grid with grid-template-rows, which animates smoothly regardless of content height and avoids fixed pixel values, as demonstrated in Web.dev's CSS UI guide. This technique pairs well with our SEO services for creating performant, accessible content sections that improve user engagement and search visibility.

Content Visibility Animation

For simpler animations, the opacity property provides a smooth fade effect that works well for subtle transitions. This approach complements our AI-powered interfaces where smooth transitions improve user experience without adding JavaScript complexity.

Smooth Grid Animation
1details {2 overflow: hidden;3}4 5details .content {6 display: grid;7 grid-template-rows: 0fr;8 transition: grid-template-rows 0.3s ease-out;9}10 11details[open] .content {12 grid-template-rows: 1fr;13}14 15.content-inner {16 overflow: hidden;17}

Integration Patterns

FAQ Section Implementation

FAQ sections benefit significantly from the details element, providing an organized Q&A format while keeping the page concise. Users can quickly scan questions and expand only those they want to read in detail.

Nested Details Elements

For complex content hierarchies, details elements can be nested to create multi-level expandable content. This pattern works well for documentation with expandable sections and subsections, commonly used in our technical documentation services.

Programmatic Control with the Toggle Event

The toggle event fires whenever the open state changes, enabling JavaScript integration for dynamic content loading, analytics tracking, or other side effects. This event can trigger AI model responses to load only when users request additional details.

FAQ Section Example
1<section class="faq">2 <details>3 <summary>What payment methods do you accept?</summary>4 <div class="answer">5 <p>We accept all major credit cards, PayPal, and bank transfers.</p>6 </div>7 </details>8 9 <details>10 <summary>What is your return policy?</summary>11 <div class="answer">12 <p>You may return unused items within 30 days for a full refund.</p>13 </div>14 </details>15</section>

Accessibility Considerations

The <details> and <summary> elements have built-in accessibility features that should be maintained through careful styling.

Maintaining Keyboard Navigation

The <summary> element is naturally focusable and responds to keyboard activation via Enter or Space keys. Custom markers should not interfere with this behavior. When using pseudo-elements for markers, ensure they don't capture pointer events.

Screen Reader Considerations

Screen readers announce the disclosure state appropriately when using native elements. When adding icons or additional visual indicators, use aria-hidden to prevent duplicate announcements.

Focus Indicators

Ensure visible focus indicators remain visible when styling the summary element for keyboard users. Following MDN's accessibility guidelines ensures inclusive experiences for all visitors.

Accessibility Best Practices
1/* Prevent pseudo-elements from capturing clicks */2summary::before {3 pointer-events: none;4}5 6/* Ensure visible focus indicators */7summary:focus {8 outline: 2px solid #0066cc;9 outline-offset: 2px;10}

Performance Optimization

The details element provides excellent performance characteristics due to its native implementation and lack of required JavaScript.

Lazy Loading Content

For performance-critical pages with many details elements, content can be loaded dynamically when the widget opens. This approach reduces initial page weight by deferring content loading until users request it.

Minimizing Layout Thrashing

When animating details elements, batch read and write operations using requestAnimationFrame to minimize layout recalculations and ensure smooth animations. This optimization technique is essential for pages with AI-generated content that may have variable content lengths.

Lazy Loading Content
1details.addEventListener('toggle', async function() {2 if (this.open && !this.dataset.loaded) {3 const response = await fetch(this.dataset.url);4 const html = await response.text();5 this.querySelector('.content').innerHTML = html;6 this.dataset.loaded = 'true';7 }8});

Frequently Asked Questions

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Sources

  1. MDN Web Docs - HTML details element - Official documentation for details element attributes, events, and accessibility

  2. Chrome for Developers - More options for styling details - New CSS features including ::details-content pseudo-element and display property support

  3. MDN Web Docs - ::details-content CSS selector - Browser support information for the new pseudo-element

  4. Web.dev - Exclusive accordion pattern - Modern accordion implementation patterns using CSS

  5. LogRocket - Styling HTML details and summary with modern CSS - Comprehensive styling guide with animation techniques