body { font-family: Arial, sans-serif; margin: 0; padding: 0; background: #f5f5f5; }
header { background: #333; color: white; padding: 20px; text-align: center; }
nav a { margin: 0 10px; color: white; text-decoration: none; }
section { padding: 20px; }
img { max-width: 100%; height: auto; }

body {
    background: url('../images/background.png') no-repeat center center fixed;
    background-size: cover;
}