<div class="wrapper">
  <div class="element"></div>
</div>

body{
  background-color: black;
}
.wrapper{
  height: 60vh;
  vertical-align: center;
  box-sizing: border-box;
}
.element{
  width: 80vw;
  height: 2vw;
/*   outline: 2px dashed red; */
  background: radial-gradient(ellipse, rgba(255,255,255,0.2) 0%, transparent 75%);
  background-size: 100% 200%;
  background-repeat: no-repeat;
  background-position: 0 120%;
  margin: auto;
  margin-top: 5%;
  
}