html.site-background-active body {
    background-image: var(--site-background-image) !important;
    background-position: center !important;
    background-size: cover !important;
    background-repeat: no-repeat !important;
    background-attachment: fixed !important;
}
html.site-background-active body::before,
html.site-background-active body::after { display: none !important; }