The class needs to be applied on the parent, which is <nav>
Edit: Since there is more content inside the nav, the justify-content-end class would not work as intended. You need to use ml-auto
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/>
<nav class="navbar navbar-expand-lg navbar-light bg-light col-12">
<h1>H1 tag</h1>
<ul class="nav ml-auto">
<li class="nav-item">
<a class="nav-link active" href="#">Active</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Disabled</a>
</li>
</ul>
</nav>
Answer from Anurag Srivastava on Stack OverflowVideos
The class needs to be applied on the parent, which is <nav>
Edit: Since there is more content inside the nav, the justify-content-end class would not work as intended. You need to use ml-auto
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/>
<nav class="navbar navbar-expand-lg navbar-light bg-light col-12">
<h1>H1 tag</h1>
<ul class="nav ml-auto">
<li class="nav-item">
<a class="nav-link active" href="#">Active</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Disabled</a>
</li>
</ul>
</nav>
Assuming you're trying to align the nav on the right end of the navbar, it would be:
<nav class="navbar navbar-expand-lg navbar-light bg-light justify-content-end">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link active" href="#">Active</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Disabled</a>
</li>
</ul>
</nav>
https://codeply.com/p/u2Xl8bTym0
I have changed your code a little to get the desired effect.
On <div class="row"> i removed some unneeded styles.
and on the <div class="col"> i changed it to col-4 to set the width.
Since bootstrap works in a frame of 12. 4 + 4 leaves 4 short so thats the space thats being filled with justify-content-between.
I also deleted your css since it was not needed.
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<body class="d-flex flex-column min-vh-100">
<!-- -->
<nav class="navbar navbar-light navbar-expand-md bg-light">
<div class="container-fluid">
<a class="navbar-brand" href="#">
<img src="img/logo.svg" alt="">
</a>
<!-- -->
<div class="navbar-nav d-none d-md-flex">
<a class="nav-link active" aria-current="page" href="#">Home</a>
<a class="nav-link" href="#">A</a>
<a class="nav-link" href="#">B</a>
<a class="nav-link" href="#">C</a>
<a class="nav-link" href="#">D</a>
<a class="nav-link" href="#">E</a>
</div>
<!-- -->
<span>
<a href="https://twitter.com/" rel="nofollow noopener noreferrer"><i
class="fab fa-twitter mx-2 gstwitterblue"></i></a>
<a href="https://www.linkedin.com/"
rel="nofollow noopener noreferrer"><i class="fab fa-linkedin mx-2 gslinkedinblue"></i></a>
</span>
</div>
</nav>
<main class="flex-fill">
<div class="container d-none d-md-flex flex-md-row">
<div class="row justify-content-between">
<div class="col-4">
<div class="card">
<div class="ratio ratio-16x9">
<iframe src="https://www.youtube-nocookie.com/embed/wm48_VrbB4Q?rel=0" allowfullscreen></iframe>
</div>
<div class="card-body">
<p class="card-text">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam efficitur orci malesuada sem lacinia, vitae tempor tellus auctor. Sed elementum iaculis quam ac consectetur. Nam ac laoreet est, ut placerat arcu. Ut viverra, quam vitae gravida ornare, arcu felis elementum elit, a pulvinar lacus augue ac nisl. Nunc tincidunt ultricies luctus. Donec et congue ex. Curabitur lacinia scelerisque imperdiet. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aenean ultricies, mauris at ultricies dapibus, urna nisl ullamcorper libero, ac dictum ex neque sed ante. Pellentesque luctus nibh libero, consequat vulputate eros porttitor vitae.</p>
</div>
</div>
</div>
<div class="col-4">
<div class="card gscustomwidth">
<div class="ratio ratio-16x9">
<iframe src="https://www.youtube-nocookie.com/embed/wm48_VrbB4Q?rel=0" allowfullscreen></iframe>
</div>
<div class="card-body">
<p class="card-text">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam efficitur orci malesuada sem lacinia, vitae tempor tellus auctor. Sed elementum iaculis quam ac consectetur. Nam ac laoreet est, ut placerat arcu. Ut viverra, quam vitae gravida ornare, arcu felis elementum elit, a pulvinar lacus augue ac nisl. Nunc tincidunt ultricies luctus. Donec et congue ex. Curabitur lacinia scelerisque imperdiet. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aenean ultricies, mauris at ultricies dapibus, urna nisl ullamcorper libero, ac dictum ex neque sed ante. Pellentesque luctus nibh libero, consequat vulputate eros porttitor vitae. </p>
</div>
</div>
</div>
</div>
</div>
</main>
<!-- Standard Footer -->
<footer class="bg-light py-3 d-none d-md-flex">
<div class="container d-flex justify-content-between">
<span class="text-dark fw-lighter">Copyright 2020 Foobar Ltd. All rights reserved.</span>
<span class="text-dark fw-lighter"><a href="#" class="text-reset text-decoration-none">Legal
Information</a></span>
</div>
</footer>
</body>
The reason what you want doesn't happen is because you're not giving the row div a full width. From your code, add w-100 to the following div:
<div class="row row-cols-1 row-cols-md-2 justify-content-between">