---
title: "Accordion & Dialog"
description: "Native disclosure and modal patterns. No JavaScript required for accordion; dialog uses the native showModal() API."
layout: docs
weight: 45
type: docs
date: 2026-04-09
tags: ["components", "interactive", "reference"]
ai-disclosure: "generated"
ai-model: "claude-sonnet-4-5"
ai-provider: "Anthropic"

---

## Accordion

Style native `<details>`/`<summary>` elements. No JS needed — the browser handles open/close state.

```html
<details>
  <summary>What is agentic HTML?</summary>
  <p>Agentic HTML is structured markup generated by AI agents — semantic, predictable, and styled without classes.</p>
</details>
```

**Live example:**

<details>
  <summary>What is agentic HTML?</summary>
  <p>Agentic HTML is structured markup generated by AI agents — semantic, predictable, and styled without classes.</p>
</details>

<details>
  <summary>Why no classes?</summary>
  <p>Language models reliably produce semantic HTML. Class names require memorisation and drift. Data-attributes are explicit and grep-friendly.</p>
</details>

---

## Grouped Accordion

Wrap in `<div data-role="accordion">` for flush connected borders.

```html
<div data-role="accordion">
  <details>
    <summary>Reset layer</summary>
    <p>Normalises browser defaults without imposing opinions.</p>
  </details>
  <details>
    <summary>Token layer</summary>
    <p>Open Props foundation plus ASW semantic aliases.</p>
  </details>
  <details open>
    <summary>Components layer</summary>
    <p>Buttons, forms, accordion, dialog — all zero-class.</p>
  </details>
</div>
```

**Live example:**

<div data-role="accordion">
  <details>
    <summary>Reset layer</summary>
    <p>Normalises browser defaults without imposing opinions.</p>
  </details>
  <details>
    <summary>Token layer</summary>
    <p>Open Props foundation plus ASW semantic aliases.</p>
  </details>
  <details open>
    <summary>Components layer</summary>
    <p>Buttons, forms, accordion, dialog — all zero-class.</p>
  </details>
</div>

---

## Dialog

Native `<dialog>` element. Use `dialog.showModal()` for a modal with backdrop, or `dialog.show()` for a non-modal popover.

```html
<dialog id="demo-dialog">
  <header><h2>Confirm action</h2></header>
  <p>Are you sure you want to proceed? This cannot be undone.</p>
  <footer>
    <button onclick="document.getElementById('demo-dialog').close()">Cancel</button>
    <button onclick="document.getElementById('demo-dialog').close()">Confirm</button>
  </footer>
</dialog>

<button onclick="document.getElementById('demo-dialog').showModal()">Open dialog</button>
```

**Live example:**

<dialog id="demo-dialog">
  <header><h2>Confirm action</h2></header>
  <p>Are you sure you want to proceed? This cannot be undone.</p>
  <footer>
    <button onclick="document.getElementById('demo-dialog').close()">Cancel</button>
    <button onclick="document.getElementById('demo-dialog').close()">Confirm</button>
  </footer>
</dialog>

<button onclick="document.getElementById('demo-dialog').showModal()">Open dialog</button>

---

## Notes

- Accordion uses `:not(nav details)` scoping so nav dropdowns are unaffected.
- Dialog backdrop uses `color-mix()` for transparency — no hardcoded rgba values.
- All spacing uses Open Props / ASW tokens (`--space-*`, `--radius-*`, `--shadow-*`).
- `dialog::backdrop` uses `backdrop-filter: blur(4px)` for frosted glass effect.