.page-navigation-progress {
    position: fixed;
    inset: 0 0 auto;
    height: 4px;
    overflow: hidden;
    z-index: 1100;
    pointer-events: none;
    background: rgba(176, 139, 65, .15);
}
.page-navigation-progress[hidden] { display: none; }
.page-navigation-progress::before {
    content: '';
    display: block;
    width: 35%;
    height: 100%;
    margin-inline-start: 0;
    background: linear-gradient(90deg, #ad812d, #e9c777, #ad812d);
    box-shadow: 0 0 6px rgba(173, 129, 45, .5);
    animation: page-navigation-progress 1.25s ease-in-out infinite;
}
@keyframes page-navigation-progress {
    from { transform: translateX(0); }
    to { transform: translateX(-290%); }
}
@media (prefers-reduced-motion: reduce) {
    .page-navigation-progress::before { width: 100%; animation: none; }
}