Accordion flush variant in Bootsrap

Introduction

An accordion helps show or hide content in sections. The flush variant removes outer borders for a cleaner look.

You want to organize FAQs on a webpage without extra borders.

You need collapsible content inside a card or container with a seamless style.

You want a simple list of expandable items that blend with the background.

You want to save space by hiding details until the user clicks.

You want a modern, minimal style for your collapsible content.

Syntax

Bootsrap

<div class="accordion accordion-flush" id="accordionFlushExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="flush-headingOne">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseOne" aria-expanded="false" aria-controls="flush-collapseOne">
        Accordion Item #1
      </button>
    </h2>
    <div id="flush-collapseOne" class="accordion-collapse collapse" aria-labelledby="flush-headingOne" data-bs-parent="#accordionFlushExample">
      <div class="accordion-body">Content for item 1.</div>
    </div>
  </div>
  <!-- Repeat accordion-item for more items -->
</div>

Add accordion-flush class to remove outer borders and spacing.

Use unique IDs for each collapse section and link them with aria-controls and aria-labelledby.

Examples

A simple flush accordion with one item that starts closed.

Bootsrap

<div class="accordion accordion-flush" id="accordionFlushExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="flush-headingOne">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseOne" aria-expanded="false" aria-controls="flush-collapseOne">
        First Item
      </button>
    </h2>
    <div id="flush-collapseOne" class="accordion-collapse collapse" aria-labelledby="flush-headingOne" data-bs-parent="#accordionFlushExample">
      <div class="accordion-body">This is the first item's content.</div>
    </div>
  </div>
</div>

This flush accordion item is open by default using show class.

Bootsrap

<div class="accordion accordion-flush" id="accordionFlushExample">
  <div class="accordion-item">
    <h2 class="accordion-header" id="flush-headingTwo">
      <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseTwo" aria-expanded="true" aria-controls="flush-collapseTwo">
        Second Item (Open)
      </button>
    </h2>
    <div id="flush-collapseTwo" class="accordion-collapse collapse show" aria-labelledby="flush-headingTwo" data-bs-parent="#accordionFlushExample">
      <div class="accordion-body">This content is visible on page load.</div>
    </div>
  </div>
</div>

Sample Program

This example shows a flush accordion with three sections. Each section is collapsed by default. Clicking a header expands that section's content. The flush style removes outer borders for a clean look.

Bootsrap

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>Bootstrap Accordion Flush Example</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet" />
</head>
<body>
  <main class="container my-4">
    <h1>Accordion Flush Variant</h1>
    <div class="accordion accordion-flush" id="accordionFlushExample">
      <div class="accordion-item">
        <h2 class="accordion-header" id="flush-headingOne">
          <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseOne" aria-expanded="false" aria-controls="flush-collapseOne">
            Section 1
          </button>
        </h2>
        <div id="flush-collapseOne" class="accordion-collapse collapse" aria-labelledby="flush-headingOne" data-bs-parent="#accordionFlushExample">
          <div class="accordion-body">
            This is the content of section 1. It is hidden until you click the header.
          </div>
        </div>
      </div>
      <div class="accordion-item">
        <h2 class="accordion-header" id="flush-headingTwo">
          <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseTwo" aria-expanded="false" aria-controls="flush-collapseTwo">
            Section 2
          </button>
        </h2>
        <div id="flush-collapseTwo" class="accordion-collapse collapse" aria-labelledby="flush-headingTwo" data-bs-parent="#accordionFlushExample">
          <div class="accordion-body">
            This is the content of section 2. It also starts hidden.
          </div>
        </div>
      </div>
      <div class="accordion-item">
        <h2 class="accordion-header" id="flush-headingThree">
          <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#flush-collapseThree" aria-expanded="false" aria-controls="flush-collapseThree">
            Section 3
          </button>
        </h2>
        <div id="flush-collapseThree" class="accordion-collapse collapse" aria-labelledby="flush-headingThree" data-bs-parent="#accordionFlushExample">
          <div class="accordion-body">
            This is the content of section 3. Click to expand.
          </div>
        </div>
      </div>
    </div>
  </main>
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>

Important Notes

The flush variant removes the default accordion borders and spacing for a minimal style.

Always include Bootstrap's JavaScript bundle for the accordion to work.

Use unique IDs and aria attributes for accessibility and proper toggling.

Summary

An accordion organizes content in collapsible sections.

The flush variant removes outer borders for a cleaner look.

Use Bootstrap classes accordion and accordion-flush together.

Practice

1. What is the main visual difference when using the accordion-flush class in Bootstrap's accordion component?

easy

A. It removes the default background and borders between accordion items for a seamless look.

B. It adds extra padding inside each accordion item for better spacing.

C. It changes the accordion headers to use a different font style.

D. It makes the accordion items collapsible only on hover.

Solution

1. Step 1: Understand the accordion-flush class purpose

   The accordion-flush class is designed to remove the default background color and borders between accordion items.

2. Step 2: Visual effect of accordion-flush

   This creates a seamless, flush look where accordion items appear connected without spacing or borders.

3. Final Answer:

   It removes the default background and borders between accordion items for a seamless look. -> Option A

4. Quick Check:

   accordion-flush = seamless borderless accordion [OK]

Hint: Remember flush means no gaps or borders between items [OK]

Common Mistakes:

• Thinking it adds padding instead of removing borders
• Confusing flush with changing fonts or colors
• Assuming it changes accordion behavior on hover

2. Which of the following is the correct way to apply the flush style to a Bootstrap accordion?

easy

A. <div class='accordion-flush' id='myAccordion'>

B. <div class='accordion accordion-flush' id='myAccordion'>

C. <div class='accordion flush' id='myAccordion'>

D. <div class='accordion-flush accordion' id='myAccordion'>

Solution

1. Step 1: Check Bootstrap class naming conventions

   Bootstrap requires the base class accordion plus the modifier accordion-flush together on the same element.

2. Step 2: Verify correct class order and syntax

   The correct syntax is class='accordion accordion-flush'. Other options miss the base class or use incorrect class names.

3. Final Answer:

   <div class='accordion accordion-flush' id='myAccordion'> -> Option B

4. Quick Check:

   Base + flush classes together = correct syntax [OK]

Hint: Always include base class 'accordion' with 'accordion-flush' [OK]

Common Mistakes:

• Using only 'accordion-flush' without 'accordion'
• Swapping class order incorrectly
• Using 'flush' alone as a class

3. Given the following code snippet, what will be the visual result in the browser?

<div class='accordion accordion-flush' id='accordionExample'>
  <div class='accordion-item'>
    <h2 class='accordion-header' id='headingOne'>
      <button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#collapseOne' aria-expanded='false' aria-controls='collapseOne'>
        Item 1
      </button>
    </h2>
    <div id='collapseOne' class='accordion-collapse collapse' aria-labelledby='headingOne' data-bs-parent='#accordionExample'>
      <div class='accordion-body'>Content 1</div>
    </div>
  </div>
</div>

medium

A. An accordion with flush style but Item 1 expanded by default.

B. An accordion with default borders and Item 1 expanded by default.

C. An accordion with flush style: no borders between items and a collapsed button for Item 1.

D. An accordion with default style and all items collapsed.

Solution

1. Step 1: Identify the accordion style

   The accordion-flush class is applied, so the accordion will have no borders between items (flush style).

2. Step 2: Check the button state and collapse class

   The button has class collapsed and the collapse div has class collapse (not show), so the item is collapsed by default.

3. Final Answer:

   An accordion with flush style: no borders between items and a collapsed button for Item 1. -> Option C

4. Quick Check:

   Flush + collapsed button = An accordion with flush style: no borders between items and a collapsed button for Item 1. [OK]

Hint: Look for 'accordion-flush' and 'collapsed' classes to predict style and state [OK]

Common Mistakes:

• Assuming default borders appear with flush class
• Thinking collapsed button means expanded content
• Confusing 'collapse' and 'show' classes

4. You wrote this Bootstrap accordion with flush variant, but the borders still appear between items. What is the likely cause?

<div class='accordion flush' id='accordionExample'>
  <div class='accordion-item'> ... </div>
</div>

medium

A. Missing the base accordion class alongside accordion-flush.

B. Accordion items must have flush class individually.

C. Not including Bootstrap JavaScript file.

D. Using flush instead of accordion-flush class.

Solution

1. Step 1: Check the class names used

   The code uses class='accordion flush', but the correct flush variant class is accordion-flush.

2. Step 2: Understand effect of incorrect class

   Using flush alone does nothing; the flush style is not applied, so borders remain visible.

3. Final Answer:

   Using flush instead of accordion-flush class. -> Option D

4. Quick Check:

   Correct flush class is 'accordion-flush' not 'flush' [OK]

Hint: Use exact class 'accordion-flush' for flush style [OK]

Common Mistakes:

• Typing 'flush' instead of 'accordion-flush'
• Forgetting to include 'accordion' base class
• Assuming JS affects border styles

5. You want to create a flush accordion with three items where only one item can be open at a time. Which of the following code snippets correctly implements this behavior?

hard

A. <div class='accordion accordion-flush' id='accordionFlushExample'>
<div class='accordion-item'>
<h2 class='accordion-header' id='flush-headingOne'>
<button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='false' aria-controls='flush-collapseOne'>Item 1</button>
</h2>
<div id='flush-collapseOne' class='accordion-collapse collapse' aria-labelledby='flush-headingOne' data-bs-parent='#accordionFlushExample'>
<div class='accordion-body'>Content 1</div>
</div>
</div>
<!-- Repeat for items 2 and 3 with unique IDs and same data-bs-parent -->
</div>

B. <div class='accordion accordion-flush' id='accordionFlushExample'>
<div class='accordion-item'>
<h2 class='accordion-header' id='flush-headingOne'>
<button class='accordion-button' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='true' aria-controls='flush-collapseOne'>Item 1</button>
</h2>
<div id='flush-collapseOne' class='accordion-collapse collapse show' aria-labelledby='flush-headingOne' data-bs-parent='#accordionFlushExample'>
<div class='accordion-body'>Content 1</div>
</div>
</div>
<!-- Items 2 and 3 missing data-bs-parent attribute -->
</div>

C. <div class='accordion accordion-flush' id='accordionFlushExample'>
<div class='accordion-item'>
<h2 class='accordion-header' id='flush-headingOne'>
<button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='false' aria-controls='flush-collapseOne'>Item 1</button>
</h2>
<div id='flush-collapseOne' class='accordion-collapse collapse' aria-labelledby='flush-headingOne'>
<div class='accordion-body'>Content 1</div>
</div>
</div>
<!-- Items 2 and 3 with data-bs-parent but missing unique IDs -->
</div>

D. <div class='accordion accordion-flush' id='accordionFlushExample'>
<div class='accordion-item'>
<h2 class='accordion-header' id='flush-headingOne'>
<button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='false' aria-controls='flush-collapseOne'>Item 1</button>
</h2>
<div id='flush-collapseOne' class='accordion-collapse collapse' aria-labelledby='flush-headingOne' data-bs-parent='#accordionFlushExample'>
<div class='accordion-body'>Content 1</div>
</div>
</div>
<!-- Items 2 and 3 with duplicate IDs and missing data-bs-parent -->
</div>

Solution

1. Step 1: Confirm flush style and unique IDs

   <div class='accordion accordion-flush' id='accordionFlushExample'>
     <div class='accordion-item'>
       <h2 class='accordion-header' id='flush-headingOne'>
         <button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='false' aria-controls='flush-collapseOne'>Item 1</button>
       </h2>
       <div id='flush-collapseOne' class='accordion-collapse collapse' aria-labelledby='flush-headingOne' data-bs-parent='#accordionFlushExample'>
         <div class='accordion-body'>Content 1</div>
       </div>
     </div>
     <!-- Repeat for items 2 and 3 with unique IDs and same data-bs-parent -->
   </div>

   correctly uses accordion accordion-flush and unique IDs for each item and collapse panel.

2. Step 2: Check data-bs-parent attribute for exclusive open behavior

   <div class='accordion accordion-flush' id='accordionFlushExample'>
     <div class='accordion-item'>
       <h2 class='accordion-header' id='flush-headingOne'>
         <button class='accordion-button collapsed' type='button' data-bs-toggle='collapse' data-bs-target='#flush-collapseOne' aria-expanded='false' aria-controls='flush-collapseOne'>Item 1</button>
       </h2>
       <div id='flush-collapseOne' class='accordion-collapse collapse' aria-labelledby='flush-headingOne' data-bs-parent='#accordionFlushExample'>
         <div class='accordion-body'>Content 1</div>
       </div>
     </div>
     <!-- Repeat for items 2 and 3 with unique IDs and same data-bs-parent -->
   </div>

   includes data-bs-parent='#accordionFlushExample' on each collapse div, ensuring only one item opens at a time.

3. Final Answer:

   Option A correctly implements a flush accordion with exclusive open items. -> Option A

4. Quick Check:

   Flush + unique IDs + data-bs-parent = exclusive open accordion [OK]

Hint: Use data-bs-parent with unique IDs for exclusive flush accordion [OK]

Common Mistakes:

• Missing data-bs-parent causing multiple items open
• Duplicate or missing unique IDs breaking collapse behavior
• Incorrect or missing flush class