html, body {
    margin: 0;
    padding: 0;
}
.bg {
    position: absolute;
    top: 0;
    left: 0;
    background-image: url(hosting-en-venta-actualweb.png);
    background-size: cover;
    width: 100%;
    height: 100vh;
    z-index: 100;
}