:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-2: #243447;
  --line: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #f59e0b;
  --danger: #f87171;
  --ok: #4ade80;
  --font: "IBM Plex Sans JP", "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(1000px 500px at 10% -10%, rgba(56, 189, 248, 0.12), transparent 60%),
    radial-gradient(800px 400px at 100% 0%, rgba(245, 158, 11, 0.08), transparent 55%),
    var(--bg);
  color: var(--text);
  font-family: var(--font);
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--line);
  background: rgba(15, 23, 42, 0.92);
  position: sticky;
  top: 0;
  z-index: 20;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), #0ea5e9);
  color: #08131f;
  font-weight: 800;
  font-size: 12px;
  letter-spacing: 0.03em;
}

.brand-title {
  font-weight: 700;
  font-size: 15px;
}

.brand-sub {
  font-size: 12px;
  color: var(--muted);
}

.topbar a.back-link {
  color: var(--accent);
  text-decoration: none;
  font-size: 13px;
  border: 1px solid var(--line);
  padding: 6px 12px;
  border-radius: 8px;
}
.topbar a.back-link:hover { border-color: var(--accent); }

main {
  max-width: 1180px;
  margin: 0 auto;
  padding: 28px 20px 80px;
}

.disclaimer {
  font-size: 12px;
  color: var(--muted);
  border: 1px dashed var(--line);
  border-radius: 8px;
  padding: 8px 12px;
  margin-bottom: 24px;
}

h1 {
  font-size: 26px;
  margin: 0 0 6px;
  letter-spacing: 0.02em;
}

.lede {
  color: var(--muted);
  font-size: 14px;
  max-width: 70ch;
  line-height: 1.7;
  margin-bottom: 28px;
}

section {
  margin-bottom: 40px;
}

section > h2 {
  font-size: 16px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 4px;
}

section > .section-desc {
  color: var(--muted);
  font-size: 13px;
  margin: 0 0 16px;
  max-width: 75ch;
  line-height: 1.7;
}

.stat-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 14px 16px;
}

.stat-card .label {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.stat-card .value {
  font-family: var(--mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  margin-top: 4px;
}

.checkpoint-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.checkpoint-toggle button {
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--muted);
  border-radius: 999px;
  padding: 7px 16px;
  font-size: 13px;
  cursor: pointer;
  font-family: var(--font);
}

.checkpoint-toggle button.active {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(56, 189, 248, 0.1);
}

.arch-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 16px;
}

.autoplay-btn {
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.18), rgba(167, 139, 250, 0.18));
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 999px;
  padding: 7px 18px;
  font-size: 13px;
  font-family: var(--font);
  cursor: pointer;
}
.autoplay-btn.playing {
  color: var(--accent-2);
  border-color: var(--accent-2);
}

.arch-canvas-wrap {
  background: radial-gradient(600px 300px at 20% 0%, rgba(56, 189, 248, 0.08), transparent 60%), var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 4px;
  position: relative;
}

#arch-canvas {
  width: 100%;
  height: 460px;
  display: block;
  cursor: grab;
}

.arch-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  padding: 10px 16px 14px;
  font-size: 11px;
  color: var(--muted);
}

.arch-legend span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.arch-legend .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 8px currentColor;
}

.arch-legend .dot-particle {
  background: var(--accent-2);
}

.arch-legend .line {
  width: 18px;
  height: 1px;
  background: var(--line);
  display: inline-block;
}

.two-col {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  align-items: start;
}

@media (max-width: 860px) {
  .two-col { grid-template-columns: 1fr; }
}

.detail-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px 20px;
}

.detail-panel h3 {
  margin: 0 0 4px;
  font-family: var(--mono);
  color: var(--accent-2);
  font-size: 15px;
}

.detail-panel .desc {
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 14px;
}

.detail-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  font-size: 12px;
}

.detail-grid .k { color: var(--muted); }
.detail-grid .v { font-family: var(--mono); color: var(--text); text-align: right; }

.row-strip {
  margin-top: 16px;
}

.row-strip canvas {
  width: 100%;
  height: 90px;
  display: block;
  border-radius: 8px;
  background: var(--panel-2);
}

.row-strip .caption {
  font-size: 11px;
  color: var(--muted);
  margin-top: 6px;
}

.chart-wrap {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px;
}

.chart-wrap canvas {
  max-height: 340px;
}

.explain-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.explain-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
}

.explain-card h4 {
  margin: 0 0 8px;
  font-size: 14px;
  color: var(--accent);
}

.explain-card p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.explain-card code {
  font-family: var(--mono);
  color: var(--text);
  background: rgba(148, 163, 184, 0.12);
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 12px;
}

footer.page-footer {
  text-align: center;
  color: var(--muted);
  font-size: 12px;
  padding: 24px 0;
}

.arch-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 12px;
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 14px;
  border: 1px solid var(--line);
  color: var(--muted);
}
.arch-badge.v3 {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(56, 189, 248, 0.08);
}
.arch-badge.v2 {
  border-color: var(--accent-2);
  color: var(--accent-2);
  background: rgba(245, 158, 11, 0.08);
}

.layer-roles {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 10px;
}

.layer-role-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 14px;
}

.layer-role-card .title {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent-2);
  font-weight: 700;
  margin-bottom: 4px;
}

.layer-role-card .role {
  font-size: 12px;
  color: var(--muted);
  line-height: 1.6;
}

.layer-role-card.missing {
  opacity: 0.45;
}
.layer-role-card.missing .title::after {
  content: "（このチェックポイントには存在しない）";
  font-weight: 400;
  color: var(--danger);
  font-size: 10px;
  margin-left: 6px;
}