body,
html {
    height: 98%;
    background-color: #f0f5f9;
}

.bg {
    /* The image used */
    background-image: url("../img/under_maintenance.png");
    /* Full height */
    height: 98%;
    /* Center and scale the image nicely */
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
}