
안녕하세요.
부터스트랩 카드 코드를 복사해서 붙여넣기했는데, 카드의 보더라인이 보이지 않습니다.
새로운 html 문서를 열어서 붙여넣기해도 똑같은데 뭐가 문제일까요?ㅠ

작성한 코드 및 에러 메세지
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link href="https://fonts.googleapis.com/css2?family=Gowun+Dodum&display=swap" rel="stylesheet">
<style>
* {
font-family: 'Gowun Dodum', sans-serif;
}
.box{
background-color: antiquewhite;
width: 100%;
height: 200px;
color: white;
background-image: linear-gradient(0deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)),url(https://movie-phinf.pstatic.net/20210715_95/1626338192428gTnJl_JPEG/movie_image.jpg);
background-position: center;
background-size: cover;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
.box > button{
width: 200px;
height: 50px;
background-color: transparent;
color: white;
border-color: white;
border: 1px solid white;
border-radius: 25px;
}
.box > button:hover{
border: 2px solid white;
}
</style>
</head>
<body>
<div class="box">
<h1> 내 생애 최고의 영화들</h1>
<button> 영화 기록하기 </button>
</div>
<div class="row row-cols-1 row-cols-md-3 g-4">
<div class="col">
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional
content. This content is a little bit longer.</p>
</div>
</div>
</div>
<div class="col">
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional
content. This content is a little bit longer.</p>
</div>
</div>
</div>
<div class="col">
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional
content.</p>
</div>
</div>
</div>
<div class="col">
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional
content. This content is a little bit longer.</p>
</div>
</div>
</div>
</div>
</body>
</html>
