CSS Help: Blurred Background behind Category/Topic Lists

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2

For blurred backgrounds you can use:

body::after {
    content: "";
    background-size: cover;
    background-image: url(imageurl);
    opacity: 0.3;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    position: fixed;
    z-index: -1;
    width: 100vw;
    height: 100vh;
    filter: blur(10px);
}