body {
    background: url(bg.jpg) no-repeat center;
    background-size: cover;
    overflow: hidden;
}
body::before {
    content: '';
    background: inherit;
    position: absolute;
    top: -3px;
    bottom: -3px;
    left: -3px;
    right: -3px;
    filter: blur(3px);
    z-index: -1;
}
p {
    margin: 300px 0 200px;
    text-align: center;
    font-size: 34px;
    color: #ffffff;
}