body {
    font-family: Arial;
    margin: 0;
    background-image: url('https://images.unsplash.com/photo-1500530855697-b586d89ba3ee');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    background-color: rgba(0,0,0,0.4);
    background-blend-mode: darken;
}
header {
    background: rgba(255,255,255,0.75);
    padding: 40px;
    text-align: center;
}
.content {
    padding: 20px;
    max-width: 900px;
    margin: 30px auto;
    background: rgba(255,255,255,0.85);
    border-radius: 10px;
}
footer {
    text-align: center;
    padding: 15px;
    background: rgba(255,255,255,0.7);
    margin-top: 30px;
}