グリットレイアウトにしたはずなのに<p>タグの文字が突き抜ける

html
1<!doctype html>
2<html lang="ja">
3  <head>
4    <!-- Required meta tags -->
5    <meta charset="utf-8">
6    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
7
8    <!-- Bootstrap CSS -->
9    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
10
11    <title>Dotinstall App</title>
12    <style>
13    .cover{
14      background: url(img/bg.png);
15      background-size: cover;
16    }
17    </style>
18  </head>
19  <body>
20<header>
21  <div class="cover text-white text-center py-5">
22    <h1 class="display-4 mb-4">Dotinstall App</h1>
23    <a href= "" class="btn btn-primary btn-la">Get It Now!</a>
24  </div>
25</header>
26<main>
27  <section class="py-5">
28    <h2 class="text-center mb-5">Features</h2>
29    <div class="container">
30      <div class="mb-5 row">
31        <div class="col-sm-8">
32          <h3>Awesome</h3>
33          <p>Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.</p>
34        </div>
35      <div class="col-sm-4">
36        <img src="img/phone.png" class="w-100 rounded-circle">
37      </div>
38    </div>
39      <div class="row">
40        <div class="col-sm-8">
41          <h3>Awesome</h3>
42          <p>Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.Hello.</p>
43        </div>
44      <div class="col-sm-4">
45        <img src="img/movie.png" class="w-100 rounded-circle">
46      </div>
47      </div>
48    </div>
49  </section>
50</main>
51<footer>
52</footer>
53    <!-- Optional JavaScript -->
54    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
55    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
56    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
57    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
58  </body>
59</html>
60