The issue arises from the Bootstrap library's internal row class setting of -bs-gutter-x: 1.5rem;. By manually overriding this property, you can resolve the problem as desired. However, it's important to note that changing the behavior of the library in this manner can lead to unforeseen side effects and is generally not recommended. For a more appropriate solution, I recommend following the steps outlined in the "Suggestion" section.
<!doctype html>
<html lang="en>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Bootstrap demo</title>
<link href="https://cdn.jsdelivr.net/npm/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="caa8a5a5beb9beb8abba8affe4f8e4fa">[email protected]</a>/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-gH2yIJqKdNHPEq0n4Mqa/HGKIhSkIHeL5AyhkYV8i59U5AR6csBvApHHNl/vI1Bx" crossorigin="anonymous">
<style>
.row {
--bs-gutter-x: 0rem !important;
}
</style>
</head>
<body>
<div class="pt-5 bg-info"></div>
<div class="row pt-4 bg-success"></div>
</body>
</html>
https://i.sstatic.net/AXMFa.png
Suggestion
The pt class is utilized for adjusting the padding-top property, and its alternative use is irrelevant to the issue at hand. For responsive horizontal alignment of elements, ensure child <div> elements have a parent <div> with the classes row and container.
<link href="https://cdn.jsdelivr.net/npm/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c4a6ababb0b7b0b6a5b484f1eaf6eaf4">[email protected]</a>/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-gH2yIJqKdNHPEq0n4Mqa/HGKIhSkIHeL5AyhkYV8i59U5AR6csBvApHHNl/vI1Bx" crossorigin="anonymous">
<div class="container">
<div class="row">
<div class="pt-5 bg-info"></div>
</div>
<div class="row">
<div class="pt-4 bg-success">
</div>
</div>
References