Cannot get blurry background when Bootstrap modal is opened - html

Question

I am using Bootstrap 5.1.3 and I would like to blur the background when a modal opens with the CSS backdrop-filter property.
The simplest approach I tried is:
.modal-backdrop {
backdrop-filter: blur(5px);
}
Live demo here: https://codepen.io/kikosoft/pen/YzjxOQm
I am using the latest Firefox browser, but the results are the same in Chrome (Windows 11).
I tried many variants suggested everywhere, but none of them work. The background simply never gets blurred. Can anybody get the background to blur with backdrop-filter? What am I missing here?

Answer 1

You need to change in CSS and HTML structure according below code.
Using backdrop-filter
.modal-open .modal-backdrop {
backdrop-filter: blur(5px);
background-color: rgba(0, 0, 0, 0.5);
opacity: 1 !important;
}
<script src="//cdn.jsdelivr.net/npm/bootstrap#5.1.3/dist/js/bootstrap.min.js"></script>
<link href="//cdn.jsdelivr.net/npm/bootstrap#5.1.3/dist/css/bootstrap.min.css" rel="stylesheet"/>
<h1>This text should get blurred when the modal is opened.</h1>
<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#exampleModal">
Launch demo modal
</button>
<!-- Modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
</div>
<div class="modal-body">
...
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Save changes</button>
</div>
</div>
</div>
</div>
Using filter
.modal-open .main-wrapper {
filter: blur(5px);
}
<script src="//cdn.jsdelivr.net/npm/bootstrap#5.1.3/dist/js/bootstrap.min.js"></script>
<link href="//cdn.jsdelivr.net/npm/bootstrap#5.1.3/dist/css/bootstrap.min.css" rel="stylesheet"/>
<div class="main-wrapper">
<h1>This text should get blurred when the modal is opened.</h1>
<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#exampleModal">
Launch demo modal
</button>
</div>
<!-- Modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
</div>
<div class="modal-body">
...
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Save changes</button>
</div>
</div>
</div>
</div>

Answer 2

i dont have enough rep for comment so i write my answer here:
you should apply your style to #exampleModal
#exampleModal {
backdrop-filter: blur(5px);
}