부트스트랩4 세로 중앙 정렬

부트스트랩4 세로 중앙 정렬

<div class="card card-default">
   
   <div class="card-body">
      
      <!--- vertical-align for row --->
      <div class="container">
         <div class="row align-items-center">
            <div class="col-12 text-center">
               <!-- null-->
            </div>
         </div>
      </div><!--- vertical-align for column --->
      <div class="container">
         <div class="row" style="height: 300px;">
            <div class="col-12 align-self-center text-center">
               
               <h3><?=$login_id;?> 로그인 하였습니다.</h3>
               
            </div>
         </div>
      </div><!--- vertical-align for column --->
      <div class="container">
         <div class="row">
            <div class="col-12 my-auto text-center">
               <!-- null-->
            </div>
         </div>
      </div>
   
   </div>
</div>