/* Add this to your main stylesheet */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: #ffffff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transition: box-shadow 0.3s ease-in-out;
}

header.scrolled {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}