#timeline-container {
  position: relative;
  width: 100vw;
  height: calc(100vh - 70px); /* Adjust for header height */
  overflow: hidden;
  background-color: var(--bg-primary);
  user-select: none;
}

#timeline-track {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  cursor: grab;
  will-change: transform;
}
#timeline-track:active {
  cursor: grabbing;
}

/* Axis Line */
#timeline-axis-line {
  position: absolute;
  top: 50%;
  left: 0;
  height: 2px;
  background-color: var(--accent-gold-dim);
  box-shadow: 0 0 10px var(--accent-gold-glow);
  transform: translateY(-50%);
  width: 100000px; /* Large fallback width overridden dynamically */
}

/* Layers */
#era-labels-layer,
#year-markers-layer,
#events-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

#events-layer * {
  pointer-events: auto; /* Re-enable clicks for markers */
}

/* Era Labels */
.timeline-era-label {
  position: absolute;
  top: 15%;
  height: 70%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Cinzel', Georgia, serif;
  font-size: 6vw;
  font-weight: 700;
  color: var(--text-muted);
  opacity: 0.05;
  letter-spacing: 0.2em;
  white-space: nowrap;
  pointer-events: none;
}

/* Ticks / Year Markers */
.timeline-year-marker {
  position: absolute;
  top: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 50px;
}
.timeline-year-marker::before {
  content: '';
  width: 1px;
  height: 10px;
  background-color: var(--border);
}
.timeline-year-marker.major::before {
  height: 20px;
  width: 2px;
  background-color: var(--accent-gold);
}
.timeline-year-marker .year-label {
  margin-top: 12px;
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-weight: 500;
  white-space: nowrap;
}
.timeline-year-marker.major .year-label {
  color: var(--accent-gold);
  font-weight: 600;
}

/* Today line */
.today-marker {
  position: absolute;
  top: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(180deg, transparent, var(--accent-gold), transparent);
  box-shadow: 0 0 8px var(--accent-gold);
  opacity: 0.75;
  pointer-events: none;
}

/* Markers & Spans */
.event-marker {
  position: absolute;
  top: 50%;
  width: 16px;
  height: 16px;
  background-color: var(--bg-secondary);
  border: 3px solid var(--accent-gold);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.2s;
}
.event-marker:hover {
  transform: translate(-50%, -50%) scale(1.4);
  box-shadow: 0 0 15px var(--accent-gold);
  background-color: var(--accent-gold);
  z-index: 10;
}

.event-span {
  position: absolute;
  top: calc(50% - 25px); /* Offset slightly from center axis */
  height: 8px;
  background: linear-gradient(90deg, var(--accent-gold-dim), var(--accent-gold));
  border-radius: 4px;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s, height 0.2s, box-shadow 0.2s;
}
.event-span:hover {
  transform: translateY(-2px);
  height: 12px;
  box-shadow: 0 0 12px var(--accent-gold);
  z-index: 10;
}
.event-span-label {
  position: absolute;
  top: -22px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.2s;
  pointer-events: none;
}
.event-span:hover .event-span-label {
  opacity: 1;
}

/* Floating popups on hover/select */
.event-card-popup {
  position: absolute;
  bottom: calc(50% + 20px);
  transform: translateX(-50%) scale(0.95);
  opacity: 0;
  pointer-events: none;
  background: var(--glass);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  width: 250px;
  box-shadow: var(--shadow);
  transition: transform 0.2s, opacity 0.2s;
  z-index: 100;
}
.event-card-popup.active {
  opacity: 1;
  transform: translateX(-50%) scale(1);
  pointer-events: auto;
}
.event-card-popup::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border-width: 8px;
  border-style: solid;
  border-color: var(--border) transparent transparent transparent;
}
.event-card-popup h4 {
  font-size: 0.95rem;
  margin-bottom: 0.3rem;
  line-height: 1.3;
}
.event-card-popup .popup-date {
  font-size: 0.75rem;
  color: var(--accent-gold);
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.event-card-popup p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Header bar */
.timeline-header {
  height: 70px;
  background: var(--glass);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  z-index: 500;
  position: relative;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 700;
}
.logo svg {
  fill: var(--accent-gold);
}

.search-bar {
  display: flex;
  align-items: center;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.4rem 1rem;
  width: 300px;
  max-width: 100%;
  transition: var(--transition);
}
.search-bar:focus-within {
  border-color: var(--accent-gold);
  box-shadow: 0 0 0 2px var(--accent-gold-glow);
}
.search-bar input {
  background: none;
  border: none;
  color: var(--text-primary);
  margin-left: 8px;
  font-size: 0.9rem;
  width: 100%;
  outline: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 15px;
}

/* Left Filter Panel */
.filter-panel {
  position: fixed;
  top: 70px;
  left: 0;
  width: 320px;
  height: calc(100vh - 70px);
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border);
  z-index: 400;
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  padding: 2rem 1.5rem;
  overflow-y: auto;
  box-shadow: var(--shadow);
}
.filter-panel.active {
  transform: translateX(0);
}
.filter-section {
  margin-bottom: 2rem;
}
.filter-section h4 {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
}
.filter-checkbox-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.filter-checkbox-row {
  display: flex;
  align-items: center;
  cursor: pointer;
  font-size: 0.9rem;
  gap: 10px;
}
.filter-checkbox-row input {
  accent-color: var(--accent-gold);
  width: 16px;
  height: 16px;
}

/* Zoom Controls UI */
.zoom-controls {
  position: absolute;
  bottom: 30px;
  right: 30px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 100;
}
.zoom-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--glass);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  border: 1px solid var(--border);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.zoom-btn:hover {
  border-color: var(--accent-gold);
  color: var(--accent-gold);
  transform: scale(1.05);
}

/* Minimap */
#timeline-minimap {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  max-width: 800px;
  height: 40px;
  background: rgba(17, 24, 39, 0.6);
  border: 1px solid var(--border);
  border-radius: 20px;
  z-index: 100;
  backdrop-filter: blur(8px);
  overflow: hidden;
}
.minimap-viewport {
  position: absolute;
  top: 0;
  height: 100%;
  background-color: var(--accent-gold-glow);
  border-left: 2px solid var(--accent-gold);
  border-right: 2px solid var(--accent-gold);
  cursor: ew-resize;
}

/* Event Clustering Badge */
.event-cluster {
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
  background-color: var(--accent-gold-dim);
  border: 2px solid var(--accent-gold);
  color: var(--bg-primary);
  font-weight: 700;
  font-size: 0.75rem;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
}

/* Mobile Portrait vertical view styling override */
@media (max-width: 768px) {
  #timeline-container {
    height: calc(100vh - 60px);
  }
  .timeline-header {
    height: 60px;
    padding: 0 1rem;
  }
  .logo {
    font-size: 1.2rem;
  }
  .search-bar {
    width: 140px;
  }
  
  #timeline-axis-line {
    top: 0;
    left: 40px;
    width: 2px;
    height: 100000px;
    transform: none;
  }
  
  .timeline-year-marker {
    top: 0;
    left: 40px;
    transform: translateY(-50%);
    flex-direction: row;
    align-items: center;
    height: auto;
  }
  .timeline-year-marker::before {
    width: 10px;
    height: 1px;
  }
  .timeline-year-marker.major::before {
    width: 20px;
    height: 2px;
  }
  .timeline-year-marker .year-label {
    margin-top: 0;
    margin-left: 15px;
  }
  
  .event-marker {
    top: 0;
    left: 40px;
  }
  
  .event-span {
    left: 36px;
    width: 8px !important;
    height: auto; /* Width is handled by CSS, height is mapped dynamically via year coordinates */
    background: linear-gradient(180deg, var(--accent-gold-dim), var(--accent-gold));
    transform: translateX(-50%);
  }
  .event-span-label {
    top: 50%;
    left: 20px;
    transform: translateY(-50%);
  }
  
  .event-cluster {
    top: 0;
    left: 40px;
  }
  
  #timeline-minimap {
    display: none;
  }
  
  .zoom-controls {
    bottom: 20px;
    right: 20px;
  }
}