使用filter属性来设置模糊值
效果：
css样式：
<style type="text/css"> ???????.cover { ???????????width: 600px; ???????????height: 300px; ???????????position: relative; ???????????text-align: center; ???????????line-height: 300px; ???????????color: #fff; ???????????margin: 20px auto; ???????} ???????????????.cover::before { ???????????content: ""; ???????????position: absolute; ???????????top: 0; ???????????left: 0; ???????????width: 600px; ???????????height: 300px; ???????????background: transparent url(Images/picture/5.jpg) center center no-repeat; ???????????filter: blur(8px); ???????????z-index: -1; ???????????background-size: cover; ???????} ???</style>HTML结构：
<body> ???<div class="cover"> ???????<h2>背景模糊，文字清晰显示</h2> ???</div></body>
css设置背景模糊
原文地址：https://www.cnblogs.com/qianxuebing/p/9830528.html