/* Auto-reveal header on scroll up */
header {
    position: sticky;
    top: 0;
    z-index: 15;
    background: var(--bgColor-default);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

header.nav-hidden {
    transform: translateY(-100%);
}

header.nav-hidden + .page-layout,
header.nav-hidden + main.markdown-body {
    margin-top: 0;
}

@media (prefers-reduced-motion: reduce) {
    header {
        transition: none;
    }
}