/* ============================================================
   libra-periods.css — Aylık katalog overview (yıla göre gruplu)
   /books/libra-periods sayfası için
   ============================================================ */

/* Filter bar (yıl butonları) */
.filter-bar {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.filter-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-right: 4px;
}
.year-btn {
  padding: 4px 12px;
  border: 1.5px solid var(--border);
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
  background: none;
  cursor: pointer;
  font-family: var(--font-sans);
  transition: all var(--t-base);
}
.year-btn:hover {
  border-color: var(--burgundy);
  color: var(--burgundy);
}
.year-btn.active {
  background: var(--burgundy);
  border-color: var(--burgundy);
  color: var(--white);
}

/* Year group */
.year-group {
  margin-bottom: 28px;
  /* scrollIntoView için sticky header altında kalmasın; year-heading görünür olsun */
  scroll-margin-top: calc(var(--header-height) + 20px);
}
.year-heading {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--burgundy-dark);
  padding-bottom: 10px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}
.year-heading::after {
  content: '';
  display: block;
  width: 32px;
  height: 3px;
  background: var(--burgundy);
  border-radius: 2px;
}

/* Period grid */
.periods-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}
.period-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 14px 16px;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: all var(--t-base);
  cursor: pointer;
  color: var(--ink);
}
.period-card:hover {
  border-color: var(--burgundy);
  background: var(--burgundy-pale);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  color: var(--ink);
}
.period-year-tag {
  font-size: 10px;
  font-weight: 600;
  color: var(--white);
  background: var(--burgundy);
  display: inline-block;
  padding: 2px 7px;
  border-radius: 3px;
  letter-spacing: 0.04em;
  width: fit-content;
}
.period-month {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1;
}
.period-count {
  font-size: 12px;
  color: var(--muted);
  margin-top: 2px;
}
.period-count strong {
  color: var(--burgundy);
  font-weight: 600;
}

.empty-state {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 40px;
  text-align: center;
  font-family: var(--font-serif);
  font-size: 16px;
  color: var(--muted);
}

/* Responsive */
@media (max-width: 968px) {
  .periods-grid { grid-template-columns: repeat(3, 1fr); }
  .filter-bar { padding: 10px 12px; gap: 6px; }
  .year-btn { padding: 3px 10px; font-size: 11px; }
}
@media (max-width: 640px) {
  .periods-grid { grid-template-columns: repeat(2, 1fr); }
  .year-heading { font-size: 17px; }
}