CSS에서 하단 테두리 그림자 효과를 얻는 방법

box-shadow: h-shadow v-shadow blur spread color inset;

box-shadow:2px 2px 5px #000;

box-shadow:0px 0px 10px #000;

box-shadow:inset 2px 2px 5px #000;

box-shadow:0px 0px 5px 10px #000;

box-shadow:0px 15px 10px -15px #000;

box-shadow:inset 0px 15px 10px -15px #000;

<div class="box11 shadow"></div>

.box11 {
	width: 300px;
	height: 100px;
	background: #ccc;
	border-radius: 10px;
	margin: 10px;
}

.shadow {
	position: relative;
	max-width: 270px;
	box-shadow: 0px 1px 4px rgba(0,0,0,0.3),
				0px 0px 20px rgba(0,0,0,0.1) inset;
}

.shadow::before,
.shadow::after {
   content:"";
   position:absolute;
   z-index:-1;
}

.shadow::before,
.shadow::after {
   content:"";
   position:absolute;
   z-index:-1;
   bottom:15px;
   left:10px;
   width:50%;
   height:20%;
}

.shadow::before,
.shadow::after {
   content:"";
   position:absolute;
   z-index:-1;
   bottom:15px;
   left:10px;
   width:50%;
   height:20%;
   box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
   transform:rotate(-3deg);
}

.shadow::after{
   right:10px;
   left:auto;
   transform:rotate(3deg);
 }