Mẫu gốc rộng 20px
https://codepen.io/arbaoui_mehdi/pen/nZaEpj

mẫu tự sửa 60px
<div class="shelf">
  <div class="bookend_left"></div>
	<div class="bookend_right"></div>
	<div class="reflection"></div>
</div>

.shelf {
  display: block;
  position: relative;
  width: 800px;
  height: 60px;
  margin: 100px auto 0;
  background-image: linear-gradient(90deg, #d1d8de 0%, #c3cbd6 100%);
  box-shadow: 0 2px 2px #647387, 0 4px 0 #889bae, 0 15px 18px -8px #000000;
}

.bookend_left {
  display: block;
  position: absolute;
  left: -55px;
  top: -28px;
  width: 80px;
  height: 62px;
  background-color: #ffffff;
  transform: rotate(35deg);
}

.bookend_left:before {
  position: absolute;
  top: 60px;
  left: 65px;
  width: 20px;
  height: 20px;
  background-color: #ffffff;
  content: "";
  transform: rotate(-35deg);
}

.bookend_right {
  display: block;
  position: absolute;
  right: -55px;
  top: -28px;
  width: 80px;
  height: 62px;
  background-color: #ffffff;
  transform: rotate(-35deg);
}

.bookend_right:before {
  position: absolute;
  top: 60px;
  right: 65px;
  width: 20px;
  height: 20px;
  background-color: #ffffff;
  content: "";
  transform: rotate(35deg);
}

.shelf .reflection {
  display: block;
  position: absolute;
  top: 52px;
  left: 1px;
  width: 99.8%;
  height: 1px;
  background-image: linear-gradient(0deg, rgba(255, 255, 255, 1.0) 0%, rgba(255, 255, 255, 0.5) 35%, rgba(255, 255, 255, 1.0) 65%, rgba(255, 255, 255, 0.7) 100%);
}

Cần chỉnh lại màu cho giống kính glass.

bí quyết chỉnh kích thước. các thông số left và before sẽ bằng right.
.bookend_left {
		display: block;				jjjjjjjjjjjjjjjjjjjj
		position: absolute;			ddddddddddddddd
		left: -25px;				cccccccccccccccccccccccccc
		top: -18px;					kuuuuuuuuuuuuuuuuuuuuuuuuu
		width: 36px;				xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
		height: 36px;				vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
		background-color: @color3;
//LESS Mixins
		.transform (rotate(35deg));
}

.bookend_left:before {
		position: absolute;
		top: 31px;                   ++++++++++++++++++++++++++++++++++++++++++++++
		left: 17px;
		width: 20px;                  //////////////////////////////////////
		height: 10px;
		background-color: @color3;
		content:"";
//LESS Mixins
		.transform (rotate(-35deg));
}		

chi can canh 1 ben trai voi chieu cao 60. ben con lai y nguyen nhu the

.bookend_right {
		display: block;				jjjjjjjjjjjjjjjjjjjjjjjjjj
		position: absolute;			dddddddddddddddddd
		right: -25px;				cccccccccccccccccccccccccc
		top: -18px;					kuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
		width: 36px;				xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
		height: 36px;					vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
		background-color: @color3;
//LESS Mixins
		.transform (rotate(-35deg));
}

.bookend_right:before {
		position: absolute;
		top: 31px;				+++++++++++++++++++++++
		right: 17px;
		width: 20px;            //////////////////////////
		height: 10px;
		background-color: @color3;
		content:"";
//LESS Mixins
		.transform (rotate(35deg));
}