https://getbootstrap.kr/docs/5.1/getting-started/introduction/
<body>
<div class="container">
<h1>container</h1>
</div>
<div class="container-fluid">
<h1>container-fluid</h1>
</div>
</body>
<div class="col-중단점-★">
★에 숫자를 넣어서 너비 지정<div class="container">
내용 // 불가
</div>
<div class="container">
<div class="row">
내용 // 불가
</div>
</div>