In the previous project (profile), I created this file to view. It was viewable at http://localhost:4200/assets/bootstrap.html after I started the Angular webserver with npm start.

assets/bootstrap.html
<!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@4.5.3/dist/css/bootstrap.min.css"
        integrity="sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2" crossorigin="anonymous">

  <title>Hello, world!</title>

  <style>
    div {
      /*outline: thin dashed red;*/
    }
  </style>
</head>
<body>

<div class="container-fluid">

  <nav class="navbar fixed-top navbar-expand-lg navbar-light bg-light">
    <a class="navbar-brand" href="#"><img src="http://placekitten.com/150/150" width="50" height="50"
                                          alt="Kitten Brand"/> Navbar</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>

    <div class="collapse navbar-collapse" id="navbarSupportedContent">
      <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
          <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item dropdown">
          <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown"
             aria-haspopup="true" aria-expanded="false">
            Dropdown
          </a>
          <div class="dropdown-menu" aria-labelledby="navbarDropdown">
            <a class="dropdown-item" href="#">Action</a>
            <a class="dropdown-item" href="#">Another action</a>
            <div class="dropdown-divider"></div>
            <a class="dropdown-item" href="#">Something else here</a>
          </div>
        </li>
        <li class="nav-item">
          <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
        </li>
      </ul>
      <form class="form-inline my-2 my-lg-0">
        <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
        <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
      </form>
    </div>
  </nav>
</div>

<div class="container" style="margin-top: 5em;">
  <div class="row justify-content-md-end">
    <div class="col-md-8 align-self-md-end">
      <h1>Hello, world!</h1>
    </div>
  </div>
  <div class="row justify-content-md-end">
    <div class="col-md-8 align-self-md-end">
      <div class="alert alert-info alert-dismissible fade show" role="alert">
        <strong>Holy guacamole!</strong> You should check in on some of those fields below.
        <button type="button" class="close" data-dismiss="alert" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
    </div>
  </div>
  <div class="row">
    <div class="col-md-4">
      <ul>
        <li>Nullam mollis justo quis ex accumsan lobortis.</li>
        <li>Aenean semper quam venenatis lorem aliquet, quis eleifend ipsum auctor.</li>
        <li>Fusce quis velit congue, elementum enim ac, tristique nibh.</li>
        <li>In eu mauris varius, maximus libero et, mollis ex.</li>
        <li>Nunc ornare leo vitae eros ullamcorper ultrices.</li>
      </ul>
    </div>
    <div class="col-md-8">
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed condimentum ultrices nulla, id porta justo
        scelerisque sit amet. Aliquam enim elit, lobortis non pulvinar in, tempus vel erat. In leo augue, finibus eu
        ante ac, venenatis commodo ligula. Integer at lectus a lectus laoreet egestas. Nunc mauris ex, fringilla at
        felis at, aliquam commodo eros. Suspendisse elit felis, condimentum quis mi id, elementum maximus elit. Donec
        gravida nec turpis nec efficitur. Sed lorem arcu, porta vel elit nec, accumsan feugiat lectus. Phasellus
        pharetra arcu non rutrum pretium. Vivamus auctor, eros sit amet ornare blandit, ligula erat consectetur sapien,
        id tempor eros velit ut velit.</p>
      <p>Interdum et malesuada fames ac ante ipsum primis in faucibus. Donec pretium, tortor vitae pellentesque commodo,
        felis augue molestie odio, in sodales massa sapien at ante. Donec euismod libero tincidunt, placerat quam vel,
        vestibulum sem. Integer scelerisque nibh eget tortor hendrerit, sed gravida mauris bibendum. Donec molestie
        lorem nec est consequat, eget sollicitudin nibh placerat. Etiam vitae felis eget nisl pellentesque eleifend.
        Nunc lobortis finibus tortor nec posuere. Donec id volutpat diam, sed laoreet elit. Ut egestas eros eget risus
        blandit dictum. Cras a auctor sapien, a venenatis dui. Morbi consectetur finibus velit sed consequat.</p>
      <p>Sed vulputate quis ante efficitur euismod. Sed ultricies sapien ligula. Fusce hendrerit dictum odio, in
        efficitur est feugiat a. Phasellus ut elit a turpis vestibulum iaculis. Aliquam erat volutpat. Phasellus a
        mauris quam. Sed eget ex blandit justo venenatis rutrum tempus vitae quam. Donec placerat mollis ante, vel
        mollis leo lacinia vitae. Duis id ultricies magna. Donec venenatis elit non orci vehicula, at finibus nibh
        elementum. Sed tincidunt tristique tellus, id vulputate est sagittis in. Etiam id condimentum nibh, quis
        tristique lectus.</p>
      <p>Suspendisse ornare, lorem et sodales porttitor, nisi tortor volutpat justo, sit amet commodo quam sem quis
        velit. Vivamus fringilla tempus tellus dignissim rhoncus. Duis et iaculis ex, ut aliquet enim. Sed sodales
        commodo est, vitae feugiat urna gravida in. Integer id justo ut augue commodo consectetur ut ac sem. Vestibulum
        sagittis, sem eu iaculis consectetur, mauris dolor ullamcorper ligula, in feugiat elit turpis non mi. Donec
        ornare sit amet augue vitae sollicitudin. Cras porttitor urna eget odio pharetra, hendrerit maximus nibh
        malesuada. Nam vel tincidunt augue.</p>
      <p>Aenean porttitor nulla libero, sit amet viverra turpis laoreet id. Morbi in blandit ipsum. Aenean venenatis
        erat et accumsan sodales. Fusce maximus tellus sed lacus suscipit pharetra. Suspendisse et odio mauris. Fusce
        eget augue lorem. Duis volutpat vel libero sed blandit. Quisque laoreet maximus nunc.</p>
    </div>
  </div>
</div>

<!-- Optional JavaScript; choose one of the two! -->

<!-- Option 1: jQuery and Bootstrap Bundle (includes Popper) -->
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js"
        integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj"
        crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.bundle.min.js"
        integrity="sha384-ho+j7jyWK8fNQe+A12Hb8AhRq26LrZ/JpcUGGOn+Y7RsweNrtN/tE3MoK7ZeZDyx"
        crossorigin="anonymous"></script>

<!-- Option 2: jQuery, Popper.js, and Bootstrap JS
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.min.js" integrity="sha384-w1Q4orYjBQndcko6MimVbzY0tgp4pWB4lZ7lr30WKz0vr/aWKhXdBNmNb5D92v7s" crossorigin="anonymous"></script>
-->
</body>
</html>