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>