/* Add background opacity to all pages, but login page */
body:not(#body-login)::before {
    content: " ";
    background-color: #666666;
    opacity: 1.0;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    position: absolute;
}

/* Add a partially transparent black background to navbar */
body:not(#body-login) #header::before {
    content: " ";
    background-color: black;
    opacity: 0.5;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    position: absolute;
    height: auto;
}