<title>This tests that an element with visibility hidden does not show its backdrop filter.</title>
<style>
.container {
    width: 200px;
    height: 200px;
    background: blue;
    margin: 50px;
}
.top {
    width: 400px;
    height: 50px;
    position: absolute;
    left: 0;
    top: 150px;
    border: 1px solid red;
    -webkit-backdrop-filter: blur(50px);
    visibility: hidden;
}
</style>
<body>
<div class="container"><div class="top"></div></div>