JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

.test{
  position:relative;
  height:500px;
  width:500px;
  background: linear-gradient(115deg,  #b3ddcc33 40%,#a6c0b5cc 45%,#a6c0b5cc 55%,#b3ddcc33 60%,#b3ddcc33 100%);
}
.shadow{
  position:absolute;
  width:100%;
  height:100%;
  top:0;
  bottom:0;
  background: linear-gradient(#fff 20%,transparent);
}