*, *::before, *::after {
  box-sizing: border-box;
}

body {
  background-color: var(--color-ivory-2);
  color: var(--color-text);
  font-family: var(--font-sans);
  margin: 0;
  padding: 0;
}

/* Page Layout */
.page {
  width: 100%;
  padding: 2rem 1rem;
  display: flex;
  justify-content: center;
}

.page__inner {
  width: 100%;
  max-width: var(--max-width);
}

/* Breadcrumbs */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: 1.5rem;
}

.breadcrumbs a {
  color: var(--color-copper-dark);
  text-decoration: none;
}

.breadcrumbs a:hover {
  text-decoration: underline;
}

.breadcrumbs__sep {
  color: var(--color-muted);
}

.breadcrumbs__current {
  color: var(--color-text-secondary);
  font-weight: 500;
}

/* Header & Intro */
.shelf-header {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-card);
}

.shelf-header__title {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 0.5rem 0;
  color: var(--color-text);
}

.shelf-header__meta {
  margin: 0;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.shelf-intro {
  margin: 1.25rem 0 2rem 0;
  color: var(--color-text-secondary);
  font-size: 1rem;
}

/* Shelf Section Stack */
.shelf-stack {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.shelf-unit {
  background: transparent;
}

.shelf-unit__head {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.shelf-unit__icon {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--color-copper);
}

.shelf-unit__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.shelf-unit__count {
  margin-left: auto;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--color-hover);
  color: var(--color-copper-dark);
  padding: 0.25rem 0.625rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-border);
}

/* Main Container Container */
.shelf-rack {
  position: relative;
  background: var(--color-ivory);
   
  padding: 1.5rem;
  box-shadow: var(--shadow-card);
}

.shelf-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1.25rem;
}

/* Plank completely removed */
.shelf-plank {
  display: none;
}

/* Document Cards */
.pdf-book {
  position: relative;
  background: var(--color-card);
  border: 1px solid black;
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  min-height: 160px;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  box-shadow: var(--shadow-card);
  margin-left: 6px; /* Offset for spine width */
}

/* Clean Spine Accent */
.pdf-book__spine {
  position: absolute;
  top: -1px;
  bottom: -1px;
  left: -6px;
  width: 6px;
  background: var(--color-copper);
  border-top-left-radius: var(--radius);
  border-bottom-left-radius: var(--radius);
  transition: background 0.2s ease;
}

.pdf-book__cover {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.pdf-book__badge {
  align-self: flex-start;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--color-white);
  background: var(--color-copper-dark);
  padding: 0.15rem 0.4rem;
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
}

.pdf-book__title {
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.35;
  margin-bottom: auto;
}

.pdf-book__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1rem;
  padding-top: 0.5rem;
  border-top: 1px dashed var(--color-border);
}

.pdf-book__action {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-copper-dark);
}

.pdf-book__arrow {
  width: 0.875rem;
  height: 0.875rem;
  color: var(--color-copper-dark);
  transition: transform 0.2s ease;
}

/* Hover States */
.pdf-book:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-copper-light);
}

.pdf-book:hover .pdf-book__spine {
  background: var(--color-copper-dark);
}

.pdf-book:hover .pdf-book__arrow {
  transform: translateX(3px);
}

/* Empty State */
.shelf-empty {
  padding: 2rem;
  text-align: center;
  color: var(--color-muted);
  font-size: 0.875rem;
}

/* Bottom Actions */
.shelf-actions {
  margin-top: 3rem;
}

.btn-back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--color-card);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.btn-back:hover {
  background: var(--color-hover);
  border-color: var(--color-copper-light);
  color: var(--color-copper-dark);
}

.btn-back__icon {
  width: 1rem;
  height: 1rem;
}