CSS Accordion Generator
The CSS Accordion Generator is a powerful visual generator designed to help you build modern, responsive CSS accordions without writing everything from scratch. Instead of wrestling with markup, styles, and JavaScript behavior, you can tweak layouts, colors, spacing and icons in real time and instantly see the result.
The generator supports multiple layout modes, exclusive or multi-expand behavior, smooth open/close animations, and a growing set of design presets to get you started quickly. Every adjustment updates the live preview and produces clean, production-ready HTML, CSS, and JavaScript that you can copy or download and drop straight into your project.
CSS Accordion Generator
How to Use
1. Integration (The "Copy-Paste" Method)
When you click "Copy Code", you receive a standalone HTML block. To put this into an existing website:
- CSS: Move the contents of the
<style>tag into your project’s main CSS file (e.g.,style.css). - HTML: Place the
<div class="accordion-group">...</div>exactly where you want it to appear on your page. - JS: Place the
<script>logic at the very bottom of your HTML file, just before the closing</body>tag.
2. Adding Dynamic Content
The generator creates "Section 1", "Section 2", etc. You can easily swap this for real content:
- Headers: Change the text inside the
<summary>tag. - Rich Content: You aren't limited to text! Inside
<div class="content-body">, you can add: <img>tags for product shots.<ul>and<li>for feature lists.<button>tags for "Call to Action" links.
3. Making it "Dynamic"
If you are using a framework like React, Vue, or Alpine.js, you don't need to hardcode the items. You can simply loop through an array:
<details class="acc-item" v-for="item in items">
<summary>
<span>{{ item.title }}</span>
<span class="acc-icon">▼</span>
</summary>
<div class="content-wrapper">
<div class="content-body">{{ item.description }}</div>
</div>
</details>
4. Troubleshooting Height
Because the code uses scrollHeight for smooth animations:
- Initial State: If you want one item to be open by default when the page loads, add the
openattribute and the classis-opento the<details>tag, then manually set theheightof its.content-wrappertoautoin your CSS. - Nested Elements: If you put an image inside that loads slowly, the height calculation might happen before the image is ready. It's best to give images a fixed height or use
loading="eager".
Frequently Asked Questions
What is a CSS accordion?
A CSS accordion is a UI component made up of stacked sections that can be expanded or collapsed to show or hide their content. Only the header of each section is visible by default; clicking it reveals the body content beneath. Accordions are commonly used for FAQs, product descriptions, navigation menus, and any situation where you need to present a lot of content in a compact, organised way without overwhelming the user.
Can I build a CSS accordion without JavaScript?
Yes, for basic open/close behaviour you can use the native HTML <details> and <summary> elements, which require no JavaScript at all.
The browser handles the toggle natively and the elements are fully accessible out of the box.
However, if you want smooth animated transitions when panels open and close - rather than an abrupt snap - a small amount of JavaScript is needed to calculate and animate the panel height, since CSS alone cannot reliably animate from a fixed height to height: auto.
What is the difference between exclusive and multi-expand accordions?
In an exclusive (or single-expand) accordion, only one panel can be open at a time. Opening a new panel automatically closes whichever one was previously open. This keeps the interface compact and is the most familiar pattern for users. In a multi-expand accordion, any number of panels can be open simultaneously, giving users the freedom to compare content across sections side by side. Which to use depends on your content - use exclusive when panels are alternatives, multi-expand when users may need to reference multiple sections at once.
How do I animate an accordion open and close smoothly in CSS?
The challenge is that CSS cannot transition directly to or from height: auto.
The standard approach is to use JavaScript to read the element's scrollHeight - the full expanded height - set that as an explicit pixel value before animating, then transition to height: 0 when closing.
On the CSS side, add transition: height 0.3s ease; overflow: hidden; to the content wrapper.
An alternative pure-CSS approach uses max-height with a large enough value to cover all content, but this can produce an uneven animation speed since the transition runs over the full max-height range rather than the actual content height.
How do I make one accordion panel open by default on page load?
If you are using the native <details> element, simply add the open attribute to the tag: <details open>.
If you are using a JavaScript-driven accordion, add your is-open class (or equivalent) to the panel in the HTML and set its content wrapper height to auto in your CSS so it renders at full height before any JavaScript runs.
This ensures the panel is visible even if scripts are slow to load.
Are CSS accordions accessible?
Yes, when built correctly. Using the native <details> and <summary> elements gives you keyboard navigation and screen reader support for free, since browsers expose these semantics automatically.
If you build a custom accordion using <div> elements instead, you need to add ARIA attributes manually: aria-expanded on the trigger button to indicate open/closed state, aria-controls pointing to the content panel's ID, and ensure the trigger is a <button> so it is reachable by keyboard.
Always test with a screen reader to confirm the experience is coherent.
How do I add an accordion to a React or Vue project?
The generated HTML, CSS, and JavaScript can be adapted to component-based frameworks by replacing the hardcoded items with a loop over your data array.
In React, map over your items array and render a <details> element for each one, using state to track which panels are open if you need exclusive behaviour.
In Vue, use v-for to iterate and v-bind or :class to toggle open states.
The core CSS transitions remain the same - only the templating and state management change to suit the framework's conventions.
Why is my accordion animation jerky when images are inside the panel?
This happens because the JavaScript reads scrollHeight to calculate the panel's expanded height before images have finished loading.
At the moment of calculation, unloaded images have zero height, so the value is too small - and the panel snaps or cuts off once the images appear.
The fix is to either give images a fixed height or explicit dimensions in your CSS so their space is reserved before they load, or add loading="eager" to images inside accordion panels to prioritise their load before the height is measured.
How do I change the accordion icon from a chevron to a plus/minus?
The icon is typically a CSS pseudo-element on the summary or trigger element, or an inline <span> containing the character.
To use a plus/minus, set the icon element's content to "+" by default and toggle it to "−" when the panel has an is-open class or the <details> element has the open attribute.
In CSS this looks like: details[open] .acc-icon::before { content: "−"; }.
You can also use SVG icons or icon fonts and simply rotate or swap them using a CSS transition on the open state.
What is the best HTML element to use for an accordion?
The native <details> and <summary> elements are the most semantically correct choice and provide built-in accessibility and keyboard support with no extra effort.
A <button> paired with a <div> content panel is the recommended alternative when you need more control over styling or behaviour, as long as you add the appropriate ARIA attributes.
Avoid using <a> tags as accordion triggers since anchor elements imply navigation to a new location, which is misleading for a component that simply toggles visibility on the same page.