类似高光区域(聚光灯)
效果:
<div class="box"></div>
.box {
width: 200px;
height: 200px;
background: transparent;
position: fixed;
left: 50%;
top: 50%;
transform: translate(-50%,-50%);
border: 10000px solid rgba(45, 37, 37, 0.322);
}