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Flexbox utilities

Flexbox utilities in Bootstrap provide a powerful way to create flexible layouts that adapt to various screen sizes and devices. Leveraging the Flexbox model, Bootstrap offers a set of classes that simplify the creation of responsive and dynamic designs.

Getting Started with Flexbox

Bootstrap’s Flexbox utilities are built upon the Flexbox layout model, which allows elements within a container to align, distribute, and reorder dynamically. By utilizing predefined classes, developers can control the behavior of elements with ease.

Key Flexbox Classes

Bootstrap’s Flexbox utilities consist of several classes, such as:


This class establishes an element as a flex container, enabling the use of other flex properties.

flex-row and flex-column

These classes determine the main axis of the flex container, either horizontally (flex-row) or vertically (flex-column).


Used within flex containers, these classes help in aligning items along the main axis, providing options like start, end, center, between, and around.

align-items-{value} and align-self-{value}

These classes control the alignment of items on the cross-axis. align-items applies to all items, while align-self is used on individual items within the flex container.

flex-fill, flex-grow, and flex-shrink

These classes dictate how flex items should expand (flex-grow) or shrink (flex-shrink) within a flex container, providing flexibility in layout design.

Benefits of Using Flexbox Utilities

Responsive Design

Flexbox utilities enable the creation of responsive layouts effortlessly. With classes that adjust based on screen sizes, developers can craft designs suitable for various devices.

Simplified Alignment and Distribution

Bootstrap’s Flexbox utilities simplify alignment and distribution of elements, eliminating the need for complex CSS rules and calculations.

Flexibility in Design

Developers have the flexibility to create intricate layouts and control the positioning of elements, making it easier to achieve desired design outcomes.

Implementation Example

Let’s consider an example where Flexbox utilities are used to create a responsive navbar in Bootstrap:

<nav class="navbar navbar-expand-lg navbar-light bg-light">
<div class="container-fluid">
<a class="navbar-brand" href="#">Brand</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav"
aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">

<span class="navbar-toggler-icon"></span>
<div class="collapse navbar-collapse justify-content-end" id="navbarNav">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">Home</a>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
<li class="nav-item">
<a class="nav-link" href="#">Services</a>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>