.gantt-timeline {
  --gt-bg: #FFFFFF;
  --gt-surface: #FFFFFF;
  --gt-surface-raised: #F5F5F5;
  --gt-border: #E5E7EB;
  --gt-border-subtle: #F5F5F5;
  --gt-text: #0B0B0B;
  --gt-text-muted: #6B7280;
  --gt-text-dim: #9CA3AF;
  --gt-accent: #2563EB;
  --gt-phase-plan: #818cf8;
  --gt-phase-design: #38bdf8;
  --gt-phase-build: #34d399;
  --gt-phase-finish: #fbbf24;
  --gt-phase-crisis: #f87171;
  --gt-event-dot: #374151;
  --gt-event-crisis: #f87171;
  --gt-event-milestone: #f59e0b;

  font-family: Inter, "Noto Sans JP", "Noto Sans CJK JP", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--gt-text);
  line-height: 1.6;
}

.gantt-timeline .gt-container {
  background: var(--gt-surface);
  border: 1px solid var(--gt-border);
  border-radius: 8px;
  padding: 32px;
  margin-bottom: 24px;
  min-height: 480px;
}

.gantt-timeline .gt-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 24px;
}

.gantt-timeline .gt-title {
  font-size: 1.2rem;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.gantt-timeline .gt-period {
  color: var(--gt-text-muted);
  font-size: 0.85rem;
}

.gantt-timeline .gt-meta {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 28px;
  font-size: 0.82rem;
  color: var(--gt-text-muted);
}

.gantt-timeline .gt-meta span strong {
  color: var(--gt-text);
  font-weight: 500;
}

.gantt-timeline .gt-legend {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.gantt-timeline .gt-legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  color: var(--gt-text-muted);
}

.gantt-timeline .gt-legend-swatch {
  width: 12px;
  height: 12px;
  border-radius: 3px;
}

/* Chart area */

.gantt-timeline .gt-chart {
  position: relative;
}

.gantt-timeline .gt-row {
  display: flex;
  align-items: center;
  height: 36px;
  margin-bottom: 4px;
}

.gantt-timeline .gt-label {
  width: 140px;
  min-width: 140px;
  font-size: 0.8rem;
  color: var(--gt-text-muted);
  padding-right: 12px;
  text-align: right;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.gantt-timeline .gt-track {
  flex: 1;
  position: relative;
  height: 100%;
}

/* Axis */

.gantt-timeline .gt-axis-row {
  height: 28px;
  margin-bottom: 8px;
  border-bottom: 1px solid var(--gt-border);
}

.gantt-timeline .gt-axis-label {
  position: absolute;
  bottom: 4px;
  font-size: 0.72rem;
  color: var(--gt-text-dim);
  transform: translateX(-50%);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

/* Phase bars */

.gantt-timeline .gt-bar {
  position: absolute;
  height: 22px;
  top: 7px;
  border-radius: 4px;
  opacity: 0.85;
  transition: opacity 0.15s, box-shadow 0.15s;
  cursor: default;
}

.gantt-timeline .gt-bar:hover {
  opacity: 1;
  box-shadow: 0 0 12px rgba(37, 99, 235, 0.15);
}

.gantt-timeline .gt-bar .gt-bar-tooltip {
  display: none;
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  background: rgba(11, 11, 11, 0.92);
  color: #fff;
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 0.72rem;
  white-space: nowrap;
  z-index: 10;
  border: 1px solid rgba(255,255,255,0.1);
}

.gantt-timeline .gt-bar:hover .gt-bar-tooltip { display: block; }

/* Vertical event lines */

.gantt-timeline .gt-vline {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 0;
  border-left: 1px dashed var(--gt-border);
  pointer-events: none;
  z-index: 0;
}

/* Event diamond markers */

.gantt-timeline .gt-marker-row {
  height: 32px;
  margin-top: 4px;
  margin-bottom: 0;
}

.gantt-timeline .gt-diamond {
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
  cursor: pointer;
  z-index: 5;
  width: 20px;
  height: 20px;
}

.gantt-timeline .gt-diamond::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 8px;
  height: 8px;
  background: var(--diamond-color);
  transform: translate(-50%, -50%) rotate(45deg);
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.2s;
}

.gantt-timeline .gt-diamond:hover::before {
  transform: translate(-50%, -50%) rotate(45deg) scale(1.6);
  box-shadow: 0 0 10px var(--diamond-color);
}

.gantt-timeline .gt-diamond:hover { z-index: 20; }

.gantt-timeline .gt-diamond-tooltip {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  left: 50%;
  transform: translateX(-50%);
  background: rgba(11, 11, 11, 0.94);
  color: #fff;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 0.75rem;
  z-index: 30;
  pointer-events: none;
  max-width: 300px;
  white-space: normal;
  line-height: 1.5;
  text-align: left;
  min-width: 160px;
  border: 1px solid rgba(255,255,255,0.1);
}

.gantt-timeline .gt-diamond-tooltip .gt-tt-year {
  color: #9CA3AF;
  font-size: 0.68rem;
  margin-bottom: 2px;
}

.gantt-timeline .gt-diamond:hover .gt-diamond-tooltip { display: block; }

/* Events list */

.gantt-timeline .gt-events-section {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--gt-border);
}

.gantt-timeline .gt-events-title {
  font-size: 0.78rem;
  color: var(--gt-text-dim);
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 500;
}

.gantt-timeline .gt-event-row {
  display: flex;
  align-items: flex-start;
  margin-bottom: 8px;
}

.gantt-timeline .gt-event-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  margin-top: 6px;
  margin-right: 10px;
  flex-shrink: 0;
}

.gantt-timeline .gt-event-year {
  width: 90px;
  min-width: 90px;
  font-size: 0.78rem;
  color: var(--gt-text-dim);
  font-variant-numeric: tabular-nums;
}

.gantt-timeline .gt-event-text {
  font-size: 0.82rem;
  color: var(--gt-text);
}

/* Responsive */

@media (max-width: 640px) {
  .gantt-timeline .gt-label { width: 80px; min-width: 80px; font-size: 0.72rem; }
  .gantt-timeline .gt-container { padding: 16px; }
  .gantt-timeline .gt-meta { flex-direction: column; gap: 4px; }
}