body {
    margin: 0;
    min-height: 100vh;
    font-family: 'Segoe UI', sans-serif;

    /* BACKGROUND IMAGE */
    background: 
        linear-gradient(
            rgba(0,0,0,0.45),
            rgba(0,0,0,0.45)
        ),
        url("../img/bg-login.jpg") no-repeat center center fixed;

    background-size: cover;

    display: flex;
    justify-content: center;
    align-items: center;
}