* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue",
    Arial, sans-serif;
  background:
    radial-gradient(1200px 520px at 8% -10%, rgba(148, 163, 184, 0.2), transparent 60%),
    radial-gradient(1000px 460px at 100% 0%, rgba(203, 213, 225, 0.2), transparent 58%),
    #eef1f5;
  color: #0f172a;
}

.site-header {
  background: linear-gradient(145deg, #334155, #475569 58%, #64748b);
  color: #f8fafc;
  padding: 36px 24px;
  box-shadow: 0 10px 24px rgba(51, 65, 85, 0.24);
}

.site-header h1 {
  margin: 0 0 8px;
  font-size: 34px;
  letter-spacing: -0.4px;
}

.site-header p {
  margin: 0;
  opacity: 0.92;
}

.container {
  max-width: 1120px;
  margin: 28px auto 52px;
  padding: 0 18px;
}

.card {
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: 18px;
  padding: 20px;
  margin-bottom: 18px;
  border: 1px solid rgba(255, 255, 255, 0.58);
  box-shadow:
    0 10px 28px rgba(15, 23, 42, 0.1),
    inset 0 1px 0 rgba(255, 255, 255, 0.7);
}

.muted {
  color: #5a677d;
}

.period-grid,
.region-grid {
  display: grid;
  gap: 12px;
}

.period-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.period-card,
.region-item {
  display: block;
  text-decoration: none;
  color: #111827;
  border: 1px solid #d7deee;
  border-radius: 14px;
  padding: 15px;
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
  background: rgba(255, 255, 255, 0.88);
}

.period-card:hover,
.region-item:hover,
.map-point:hover {
  transform: translateY(-2px);
  border-color: #a8b2c3;
  box-shadow: 0 12px 24px rgba(51, 65, 85, 0.14);
}

.period-card h3 {
  margin: 0 0 6px;
}

.period-card p {
  margin: 0 0 6px;
  color: #4a5568;
}

.period-card span {
  font-size: 13px;
  color: #4b5563;
}

.back-link {
  display: inline-block;
  margin-top: 10px;
  color: #e5e7eb;
  text-decoration: none;
  opacity: 0.95;
}

.map-board {
  position: relative;
  width: 100%;
  aspect-ratio: 2 / 1;
  border-radius: 18px;
  border: 1px solid rgba(148, 163, 184, 0.32);
  background-color: #e7eefb;
  background-size: 100% 100%;
  background-position: left top;
  background-repeat: no-repeat;
  overflow: hidden;
  box-shadow:
    0 14px 30px rgba(15, 23, 42, 0.18),
    inset 0 0 0 1px rgba(255, 255, 255, 0.2);
}

.map-switcher {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.map-tab {
  border: 1px solid #cbd5e1;
  background: #f8fafc;
  color: #334155;
  border-radius: 999px;
  padding: 6px 12px;
  cursor: pointer;
}

.map-tab.active {
  background: #475569;
  color: #fff;
  border-color: #475569;
}

.map-overlay {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.map-point {
  position: absolute;
  transform: translate(-50%, -50%);
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(71, 85, 105, 0.92);
  color: #fff;
  text-decoration: none;
  font-size: 13px;
  white-space: nowrap;
}

.map-hit-area {
  fill: rgba(255, 255, 255, 0.0001);
  stroke: none;
  cursor: pointer;
}

.map-area-label {
  fill: #f8fafc;
  font-size: 4.2px;
  font-weight: 500;
  letter-spacing: 0.24px;
  paint-order: stroke;
  stroke: rgba(15, 23, 42, 0.86);
  stroke-width: 0.9px;
  pointer-events: none;
  opacity: 1;
  transition: font-weight 0.15s ease, font-size 0.15s ease, filter 0.15s ease;
}

.map-area-link:hover .map-area-label,
.map-area-link:focus .map-area-label,
.map-area-link.active .map-area-label {
  font-weight: 700;
  font-size: 4.6px;
  filter: drop-shadow(0 0 4px rgba(255, 255, 255, 0.35));
}


.bullet-list li {
  margin-bottom: 8px;
  line-height: 1.55;
}

.hidden {
  display: none;
}

.error {
  margin: 30px;
  color: #b42318;
  font-weight: 600;
}