:root {
  --lab-bg: radial-gradient(circle at 0% 0%, rgba(61, 183, 255, 0.16), transparent 55%),
             radial-gradient(circle at 100% 100%, rgba(143, 123, 255, 0.14), transparent 60%),
             #040b14;
  --lab-text: #f2f7ff;
  --lab-text-muted: #9fb6d5;
  --lab-heading: #ffffff;
  --lab-heading-gradient: linear-gradient(95deg, #82e0ff 0%, #b388ff 32%, #ff6ec7 65%, #ffcf5d 100%);
  --lab-surface: rgba(15, 32, 54, 0.88);
  --lab-surface-strong: rgba(15, 36, 60, 0.95);
  --lab-card-bg: linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02));
  --lab-card-border: rgba(123, 154, 188, 0.28);
  --lab-panel-border: rgba(123, 154, 188, 0.24);
  --lab-panel-shadow: 0 30px 70px rgba(3, 10, 24, 0.55);
  --lab-card-shadow: 0 28px 64px rgba(3, 8, 22, 0.5);
  --lab-warning-bg: rgba(248, 113, 113, 0.14);
  --lab-warning-text: #ffd1d1;
  --lab-inventory-bg: rgba(56, 189, 248, 0.18);
  --lab-inventory-text: #d0f3ff;
  --lab-dynamic-bg: rgba(18, 42, 70, 0.78);
  --lab-dynamic-border: rgba(123, 154, 188, 0.32);
  --lab-slider-track: linear-gradient(90deg, #34d399, #22d3ee);
  --lab-slider-thumb: #f8fafc;
  --lab-formula-bg: rgba(8, 22, 38, 0.85);
  --lab-formula-text: #9ec5ff;
  --lab-summary-bg: rgba(15, 32, 54, 0.92);
  --lab-summary-card-bg: linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02));
  --lab-summary-border: rgba(123, 154, 188, 0.26);
  --lab-summary-text: #f7fbff;
  --lab-breakdown-text: #aec2da;
  --lab-json-bg: rgba(10, 26, 45, 0.9);
  --lab-json-border: rgba(123, 154, 188, 0.28);
  --lab-footer-text: #8da6c4;
  --lab-node-fill: rgba(255, 255, 255, 0.08);
  --lab-node-active-legacy: rgba(248, 113, 113, 0.22);
  --lab-node-active-modern: rgba(52, 211, 153, 0.2);
  --lab-graph-text: #f4f7ff;
  --lab-legacy-border: #f87171;
  --lab-modern-border: #34d399;
  --lab-legacy-link: #fca5a5;
  --lab-modern-link: #6ee7b7;
  --lab-focus-ring: 0 0 0 3px rgba(50, 152, 220, 0.45);
}

html {
  color-scheme: dark;
}

html[data-theme="light"] {
  color-scheme: light;
  --lab-bg: #f8fafc;
  --lab-text: #0f172a;
  --lab-text-muted: #475569;
  --lab-heading: #0f172a;
  --lab-heading-gradient: linear-gradient(95deg, #2563eb 0%, #0ea5e9 40%, #22c55e 85%);
  --lab-surface: #ffffff;
  --lab-surface-strong: #ffffff;
  --lab-card-bg: linear-gradient(180deg, rgba(148, 163, 184, 0.12), rgba(148, 163, 184, 0.05));
  --lab-card-border: rgba(148, 163, 184, 0.18);
  --lab-panel-border: rgba(148, 163, 184, 0.22);
  --lab-panel-shadow: 0 25px 70px rgba(15, 23, 42, 0.08);
  --lab-card-shadow: 0 25px 70px rgba(15, 23, 42, 0.06);
  --lab-warning-bg: #fee2e2;
  --lab-warning-text: #991b1b;
  --lab-inventory-bg: rgba(30, 64, 175, 0.08);
  --lab-inventory-text: #1e3a8a;
  --lab-dynamic-bg: rgba(226, 232, 240, 0.6);
  --lab-dynamic-border: rgba(148, 163, 184, 0.3);
  --lab-slider-thumb: #0f172a;
  --lab-formula-bg: rgba(255, 255, 255, 0.6);
  --lab-formula-text: #1e3a8a;
  --lab-summary-bg: #ffffff;
  --lab-summary-card-bg: linear-gradient(180deg, rgba(148, 163, 184, 0.12), rgba(148, 163, 184, 0.05));
  --lab-summary-border: rgba(148, 163, 184, 0.18);
  --lab-summary-text: #0f172a;
  --lab-breakdown-text: #475569;
  --lab-json-bg: rgba(226, 232, 240, 0.6);
  --lab-json-border: rgba(148, 163, 184, 0.28);
  --lab-footer-text: #475569;
  --lab-node-fill: #ffffff;
  --lab-node-active-legacy: #fef2f2;
  --lab-node-active-modern: #ecfdf5;
  --lab-graph-text: #0f172a;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Poppins', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--lab-bg);
  color: var(--lab-text);
  transition: background 0.35s ease, color 0.35s ease;
  min-height: 100vh;
}

body.lab-page .site-nav {
  justify-content: flex-start;
  gap: 1.25rem;
}

body.lab-page .site-nav .nav-links {
  margin-left: auto;
  gap: 1.2rem;
}

body.lab-page .nav-links .theme-toggle {
  border: 1px solid rgba(255, 255, 255, 0.16);
  background: rgba(10, 24, 40, 0.55);
  border-radius: 999px;
  padding: 0.35rem 0.85rem;
  font-size: 0.9rem;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: inherit;
  cursor: pointer;
  transition: transform 0.25s ease, background 0.25s ease, border-color 0.25s ease, color 0.25s ease;
}

body.lab-page .nav-links .theme-toggle:hover,
body.lab-page .nav-links .theme-toggle:focus-visible {
  transform: translateY(-2px);
  outline: none;
  box-shadow: var(--lab-focus-ring);
}

body.lab-page .nav-links .theme-toggle:active {
  transform: translateY(0);
}

body.lab-page .nav-links .theme-toggle[data-theme="light"] {
  border-color: rgba(15, 23, 42, 0.18);
  background: rgba(15, 23, 42, 0.08);
  color: #0f172a;
}

body.lab-page .nav-links .theme-toggle[data-theme="light"]:hover,
body.lab-page .nav-links .theme-toggle[data-theme="light"]:focus-visible {
  box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.35);
}

.theme-toggle__icon {
  font-size: 1rem;
  opacity: 0.6;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.theme-toggle__icon--sun {
  transform: rotate(-8deg);
}

.theme-toggle[data-theme="light"] .theme-toggle__icon--sun {
  opacity: 1;
  transform: scale(1.05) rotate(0deg);
}

.theme-toggle[data-theme="light"] .theme-toggle__icon--moon {
  opacity: 0.35;
  transform: scale(0.85) rotate(-12deg);
}

.theme-toggle[data-theme="dark"] .theme-toggle__icon--moon {
  opacity: 1;
  transform: scale(1.05) rotate(0deg);
}

.theme-toggle[data-theme="dark"] .theme-toggle__icon--sun {
  opacity: 0.35;
  transform: scale(0.85) rotate(-12deg);
}

@media (max-width: 880px) {
  body.lab-page .site-nav {
    align-items: center;
  }

  body.lab-page .nav-links .theme-toggle {
    width: 100%;
    justify-content: center;
    margin-top: 0.75rem;
  }
}

.lab-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
  padding: clamp(1.5rem, 2.5vw, 3rem);
}

.lab-header {
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.lab-header h1 {
  font-weight: 700;
  font-size: clamp(1.9rem, 4vw, 2.9rem);
  margin-bottom: 0.6rem;
  background: var(--lab-heading-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.lab-subtitle {
  font-weight: 400;
  margin: 0 auto 1rem;
  max-width: 520px;
  color: var(--lab-text-muted);
}

.lab-disclaimer {
  background: var(--lab-warning-bg);
  color: var(--lab-warning-text);
  padding: 0.85rem 1.2rem;
  border-radius: 14px;
  font-weight: 500;
  box-shadow: var(--lab-panel-shadow);
}

.lab-main {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.panel-heading h2,
.flow-panel h2,
.pricing-engine h2,
.summary-panel h2 {
  margin: 0 0 0.35rem;
  font-weight: 600;
  color: var(--lab-heading);
}

.panel-heading p,
.flow-panel p,
.pricing-engine p {
  margin: 0;
  color: var(--lab-text-muted);
}

.product-panel {
  background: var(--lab-surface);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: var(--lab-panel-shadow);
  border: 1px solid var(--lab-panel-border);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.2rem;
}

.product-card {
  background: var(--lab-card-bg);
  border-radius: 18px;
  padding: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  position: relative;
  border: 1px solid var(--lab-card-border);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  box-shadow: var(--lab-card-shadow);
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 28px 70px rgba(0, 0, 0, 0.45);
}

.product-card input[type="checkbox"] {
  width: 22px;
  height: 22px;
  accent-color: var(--lab-modern-border);
}

.product-card .price {
  font-weight: 600;
  font-size: 1.1rem;
}

.product-card p {
  color: var(--lab-text-muted);
  margin: 0;
}

.product-card .inventory {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.85rem;
  color: var(--lab-inventory-text);
  background: var(--lab-inventory-bg);
  padding: 0.35rem 0.6rem;
  border-radius: 999px;
  transition: transform 0.35s ease;
}

.inventory.animate {
  transform: scale(1.07);
}

.inventory-hint {
  font-size: 0.85rem;
  color: var(--lab-text-muted);
}

.flow-panel {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.flow-diagrams {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.flow-card {
  background: var(--lab-surface);
  border-radius: 24px;
  padding: 1.8rem;
  box-shadow: var(--lab-panel-shadow);
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  border-top: 8px solid transparent;
  border: 1px solid var(--lab-panel-border);
}

.flow-card.legacy {
  border-top-color: var(--lab-legacy-border);
}

.flow-card.modern {
  border-top-color: var(--lab-modern-border);
}

.flow-card header h3 {
  margin: 0;
  font-weight: 600;
  font-size: 1.4rem;
  color: var(--lab-heading);
}

.flow-sub {
  font-size: 0.85rem;
  color: var(--lab-text-muted);
  font-weight: 500;
}

.flow-description {
  color: var(--lab-text-muted);
  margin: 0.4rem 0 0;
}

.dynamic-price {
  background: var(--lab-dynamic-bg);
  border-radius: 16px;
  padding: 1rem 1.2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  color: var(--lab-summary-text);
  box-shadow: inset 0 0 0 1px var(--lab-dynamic-border);
}

.dynamic-price .value {
  font-size: 1.6rem;
}

.flow-graph {
  width: 100%;
  height: 380px;
}

.node circle {
  fill: var(--lab-node-fill);
  stroke-width: 3px;
}

.legacy .node circle {
  stroke: var(--lab-legacy-border);
}

.modern .node circle {
  stroke: var(--lab-modern-border);
}

.node text {
  font-size: 0.82rem;
  fill: var(--lab-graph-text);
  text-anchor: middle;
  pointer-events: none;
}

.link {
  fill: none;
  stroke-width: 3px;
  stroke-linecap: round;
  opacity: 0.7;
}

.legacy .link {
  stroke: var(--lab-legacy-link);
}

.modern .link {
  stroke: var(--lab-modern-link);
}

.node.active circle {
  fill: var(--lab-node-active-legacy);
}

.modern .node.active circle {
  fill: var(--lab-node-active-modern);
}

.node.pulse circle {
  animation: pulseNode 1.2s ease;
}

@keyframes pulseNode {
  0% { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0.45); }
  50% { box-shadow: 0 0 0 12px rgba(52, 211, 153, 0); }
  100% { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0); }
}

.pricing-engine {
  background: var(--lab-summary-bg);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: var(--lab-panel-shadow);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  border: 1px solid var(--lab-panel-border);
}

.slider-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}

.slider-control {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-weight: 500;
  color: var(--lab-summary-text);
}

.slider-control input[type="range"] {
  width: 100%;
  appearance: none;
  height: 6px;
  border-radius: 999px;
  background: var(--lab-slider-track);
  outline: none;
}

.slider-control input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--lab-slider-thumb);
  border: 2px solid rgba(0, 0, 0, 0.1);
  cursor: pointer;
}

.slider-control input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--lab-slider-thumb);
  border: none;
  cursor: pointer;
}

.slider-control output {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--lab-heading);
}

.formula {
  background: var(--lab-formula-bg);
  padding: 0.85rem 1rem;
  border-radius: 14px;
  font-family: 'Fira Code', 'SFMono-Regular', ui-monospace, monospace;
  color: var(--lab-formula-text);
  overflow-x: auto;
  box-shadow: inset 0 0 0 1px var(--lab-dynamic-border);
}

.summary-panel {
  background: var(--lab-summary-bg);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: var(--lab-panel-shadow);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  border: 1px solid var(--lab-panel-border);
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.summary-card {
  border-radius: 18px;
  padding: 1.6rem;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  background: var(--lab-summary-card-bg);
  border: 1px solid var(--lab-summary-border);
}

.summary-card.legacy {
  border-left: 6px solid var(--lab-legacy-border);
}

.summary-card.modern {
  border-left: 6px solid var(--lab-modern-border);
}

.summary-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--lab-summary-text);
  margin: 0;
}

.price-breakdown {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  color: var(--lab-breakdown-text);
}

.price-breakdown li {
  display: flex;
  justify-content: space-between;
  font-size: 0.95rem;
}

.json-preview {
  background: var(--lab-json-bg);
  border-radius: 16px;
  padding: 1rem 1.2rem;
  font-family: 'Fira Code', 'SFMono-Regular', ui-monospace, monospace;
  color: var(--lab-summary-text);
  box-shadow: inset 0 0 0 1px var(--lab-json-border);
}

.json-preview summary {
  cursor: pointer;
  font-weight: 600;
}

.json-preview pre {
  white-space: pre-wrap;
  word-break: break-word;
  margin: 1rem 0 0;
  max-height: 340px;
  overflow-y: auto;
}

.lab-footer {
  text-align: center;
  font-size: 0.85rem;
  color: var(--lab-footer-text);
  margin-top: auto;
}

@media (max-width: 768px) {
  .flow-graph {
    height: 320px;
  }
}

@media (max-width: 540px) {
  .product-panel,
  .flow-card,
  .pricing-engine,
  .summary-panel {
    padding: 1.4rem;
  }
}