HTML:
<div class="kr-control" @click.stop="showKrBox = !showKrBox">
<img
class="icon"
:class="{ 'arrow-down': !showKrBox }"
src="../../../../../assets/imgs/arrow-up.png"
alt=""
/>
</div>
CSS：
.kr-control::before {
background: transparent;
width: 43px;
height: 85px;
border: 4px solid #dbdfe7;
border-top: none;
border-right: none;
top: -55px;
left: -45px;
border-radius: 0 0 0 20px;
}
效果图：
