html, body {
    height: 100%;
    margin: 0;
}

body {
    display: flex;
    flex-direction: column;
    background: url('/images/background.jpg') no-repeat center center fixed;
    background-size: cover;
    image-rendering: auto;
    transition: background 0.4s ease-in-out;
}

    body.dark-mode {
        background: url('/images/darkmode.png') no-repeat center center fixed !important;
        background-size: cover;
        color: #f8f9fa;
    }

main {
    flex: 1 0 auto;
}

footer {
    flex-shrink: 0;
    font-size: 0.875rem;
}

.footer a {
    color: #f8f9fa;
    text-decoration: none;
}

    .footer a:hover {
        color: yellow;
        text-decoration: underline;
    }

.footer .footer-heading {
    font-weight: bold;
    margin-bottom: 0.5rem;
}