I am having trouble with a scrollable bootstrap modal that I want to cover with a white-transparent absolute div. I have set the modal body to a relative position and the absolute div to 100% height with top/bottom set to 0, but when scrolling, the absolute div doesn't cover the entire body.
.modal-body {
position: relative;
height: auto;
}
#loading {
background: rgba(255, 255, 255, 0.5);
width: 100%;
height: 100%;
position: absolute;
top: 0;
left: 0;
bottom: 0;
border: 1px solid red;
}<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap/dist/css/bootstrap.min.css"
integrity="sha384-xOolHFLEh07PJGoPkLv1IbcEPTNtaed2xpHsD9ESMhqIYd0nLMwNLD69Npy4HI+N" crossorigin="anonymous">
<link rel="stylesheet" href="./style.css">
<title>Bootstrap Modal</title>
</head>
<body>
<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#staticBackdrop">
Launch static backdrop modal
</button>
<!-- Modal -->
<div class="modal fade" id="staticBackdrop" data-backdrop="static" data-keyboard="false" tabindex="-1"
aria-labelledby="staticBackdropLabel" aria-hidden="true">
<div class="modal-dialog modal-dialog-scrollable">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="staticBackdropLabel">Modal title</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
<p>
Content goes here.
</p>
<div id="loading"></div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Understood</button>
</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/jquery/dist/jquery.slim.min.js"
integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj"
crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap/dist/js/bootstrap.bundle.min.js"
integrity="sha384-Fy6S3B9q64WdZWQUiU+q4/2Lc9npb8tCaSX9FK7E8HnRr0Jz8D6OP9dO5Vg3Q9ct"
crossorigin="anonymous"></script>
</body>
</html>