* {
    padding: 0;
    margin: 0;
    box-sizing:border-box;
}

body {
    display:flex;
    height:100vh;
    align-items:center;
    justify-content: center;
    overflow:hidden;
}

.background {
    background-image: url('https://images.unsplash.com/photo-1556745757-8d76bdb6984b');
    position:absolute;
    top:-20px;
    left:-20px;
    right:-20px;
    bottom:-20px;
    background-size:cover;
    background-position:center center;
    background-repeat:no-repeat;
    filter:blur(20px);
    z-index:-1;
}