JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
<div class="blur"></div>
</div>

CSS

.box{
    width: 300px;
    height: 300px;
    border: 1px solid red;
    overflow:hidden;
}

.blur{
    width: 100%;
    height: 100%;
    overflow: hidden;
    -webkit-filter: blur(20px);
    background: url("https://news.slac.stanford.edu/sites/default/files/imagecache/Img350_Scale/images/image/demag-300h.jpg");
}