.surface-hero::after {
  --surface-hero-watermark: "Époques";
}

/* ============ ERA CLUSTER ============ */
.era-wrap:nth-child(odd) {
  background: var(--surface-secondary-background);
}

.era-wrap:nth-child(even) {
  background: var(--surface-tertiary-background);
}

.era-cluster {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 3.5rem 4rem 3rem;
}

.era-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--surface-primary-foreground-muted);
  gap: 2rem;
}

.era-header-left {
  flex: 1;
}

.era-number {
  font-family: "Source Sans 3", sans-serif;
  font-size: 0.72rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--secondary-color);
  display: block;
  margin-bottom: 0.25rem;
}

.era-title {
  font-family: "Playfair Display", serif;
  font-size: clamp(1.4rem, 2.5vw, 2rem);
  font-weight: 700;
  color: var(--surface-primary-background);
  line-height: 1.1;
  margin-bottom: 0.3rem;
}

.era-date-range {
  font-family: "Source Sans 3", sans-serif;
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--primary-color);
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.era-desc {
  font-family: "EB Garamond", serif;
  font-size: 0.95rem;
  font-style: italic;
  color: var(--text-color-subtle);
  line-height: 1.5;
}

.era-count {
  font-family: "Source Sans 3", sans-serif;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--text-color-subtle);
  flex-shrink: 0;
  white-space: nowrap;
}

/* ============ PERIOD CARD GRID ============ */
.period-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem 1.25rem;
}

/* ============ PERIOD CARD ============ */
.period-card {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  transition:
    transform 0.2s ease,
    box-shadow 0.2s ease;
}

.period-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(26, 42, 66, 0.1);
}

/* Image wrapper */
.period-card-img-wrap {
  position: relative;
  aspect-ratio: 4/3;
  overflow: hidden;
  background: var(--surface-primary-foreground);
  border: 1px solid var(--surface-primary-foreground-muted);
}

.period-card-img-wrap::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--primary-color);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.period-card:hover .period-card-img-wrap::after {
  transform: scaleX(1);
}

.period-card-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: sepia(25%) contrast(1.05);
  transition:
    filter 0.3s,
    transform 0.4s;
}

.period-card:hover .period-card-img {
  filter: sepia(5%) contrast(1.1);
  transform: scale(1.03);
}

/* Date badge (top-left of image) */
.period-card-date {
  position: absolute;
  top: 0;
  left: 0;
  background: var(--surface-primary-background);
  color: var(--secondary-color);
  padding: 0.25rem 0.55rem;
  font-family: "Playfair Display", serif;
  font-size: 0.72rem;
  font-weight: 700;
  line-height: 1;
  z-index: 2;
  letter-spacing: -0.01em;
}

/* Sub-period count (top-right of image) */
.period-card-sub-badge {
  position: absolute;
  top: 0;
  right: 0;
  background: var(--primary-color);
  color: var(--background-color);
  padding: 0.2rem 0.45rem;
  font-family: "Source Sans 3", sans-serif;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  z-index: 2;
  line-height: 1.3;
}

/* Card body */
.period-card-body {
  padding: 0.7rem 0.15rem 0.5rem;
}

.period-card-title {
  font-family: "Playfair Display", serif;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--surface-primary-background);
  line-height: 1.2;
  margin-bottom: 0.2rem;
  transition: color 0.2s;
}

.period-card:hover .period-card-title {
  color: var(--primary-color);
}

.period-card-meta {
  font-family: "Source Sans 3", sans-serif;
  font-size: 0.72rem;
  color: var(--text-color-subtle);
  letter-spacing: 0.04em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.period-card-meta strong {
  color: var(--secondary-color);
  font-weight: 600;
}

.period-card-meta .sep {
  color: var(--surface-primary-foreground-muted);
}

/* Highlighted / major period — spans 2 columns */
.period-card.major {
  grid-column: span 2;
}

.period-card.major .period-card-img-wrap {
  aspect-ratio: 2/1;
}

.period-card.major .period-card-date {
  font-size: 1rem;
  padding: 0.35rem 0.75rem;
}

.period-card.major .period-card-title {
  font-size: 1.2rem;
}

.period-card.major .period-card-img-wrap::after {
  background: var(--secondary-color);
}

/* ============ RESPONSIVE ============ */
@media (max-width: 860px) {
  .era-cluster {
    padding: 2.5rem 1.5rem 2rem;
  }

  .era-header {
    flex-direction: column;
    gap: 0.5rem;
  }

  .period-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
  }

  .period-card.major {
    grid-column: span 2;
  }

}

@media (max-width: 480px) {
  .era-cluster {
    padding: 2rem 1.25rem 1.5rem;
  }

  .era-title {
    font-size: 1.3rem;
  }

  .period-grid {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .period-card.major .period-card-img-wrap {
    aspect-ratio: 4/3;
  }

  .period-card.major .period-card-title {
    font-size: 1rem;
  }
}

/* ============ FADE-IN ANIMATION ============ */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition:
    opacity 0.45s ease,
    transform 0.45s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}