/* The frame is decoration only; native active/focus states remain the fallback. */
.book-nav-marker { display: none; }
@media screen and (min-width: 768px) and (prefers-reduced-motion: no-preference) {
  aside.book-binding[data-book-marker] .book-nav-marker {
    display: block;
    position: absolute;
    inset-block-start: 0;
    inset-inline-start: 0;
    box-sizing: border-box;
    pointer-events: none;
    user-select: none;
    z-index: 0;
    background: var(--book-wash);
    border-inline-start: 1px solid var(--book-accent);
  }
  aside.book-binding[data-book-marker] a.book-nav-link {
    z-index: 1;
    color: inherit !important;
    background-color: transparent !important;
    border-inline-start-color: transparent !important;
  }
  aside.book-binding[data-book-marker] a.book-nav-link::after {
    animation: none !important;
    opacity: 0 !important;
  }
  aside.book-binding[data-book-marker] .book-nav-number {
    background-color: transparent !important;
    color: inherit !important;
    border-color: var(--book-rule) !important;
    outline: none !important;
  }
}