Example

by Vengatesh rkv

HTML

<!-- Learn about this code on MDN: https://developer.mozilla.org/en-US/docs/Web/CSS/backdrop-filter -->

<div class="container">
  <div class="box">
    <p>backdrop-filter: blur(10px)</p>
  </div>
</div>

CSS

.box {
  background-color: rgba(0, 0, 0, 0.3);
  border-radius: 5px;
  font-family: sans-serif;
  text-align: center;
  line-height: 1; 
  backdrop-filter: blur(50px);  
  -webkit-backdrop-filter: blur(50px);
  max-width: 50%;
  max-height: 50%;
  padding: 20px 40px;
}

html,
body {
  height: 100%;
  width: 100%;
}

body {
  background-image: url('https://lorempixel.com/400/200/');
  background-position: center center;
  background-repeat: no-repeat;
  background-size: cover;
}

.container {
  align-items: center;
  display: flex;
  justify-content: center;
  height: 100%;
  width: 100%;
}