.parallax-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('../img/element/BG.jpg');
    background-repeat: repeat;
    background-size: 500px 500px;
    z-index: -1;
}

.content {
    position: relative;
    background: transparent;
}