JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div class="content">
    Hello world
    </div>
</div>

CSS

#wrapper {
	margin: 0 auto;
	width: 70%;
	border: #000000 solid 1px;
	overflow: hidden !important;
}
.content:before {
  content: "";
  position: absolute;
  z-index: -1;
  background-image: url(http://images.all-free-download.com/images/graphiclarge/abstract_yellow_vector_background_148707.jpg);
  background-repeat: no-repeat;
  background-size: cover;
  width: 100%;
  height: 100%;
  filter: blur(3px);
  	-webkit-filter: blur(3px);
  	   -moz-filter: blur(3px);
  		-ms-filter: blur(3px);
		 -o-filter: blur(3px);
}

.content {
  z-index: 0;
  overflow:hidden;
  position: relative
}