@import url("https://fonts.googleapis.com/css2?family=Lato:wght@300;400;700&family=Open+Sans:wght@600;700&display=swap");

:root {
  color-scheme: light;
  --card-bg: var(--surface-card);
  --card-border: var(--border-default);
  --accent: var(--fountain-blue);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans, "Lato", Arial, sans-serif);
  color: var(--text-primary);
  background: var(--surface-muted);
  min-height: 100vh;
}

h1,
h2,
h3 {
  font-family: var(--font-display, "Open Sans", "Lato", sans-serif);
  color: var(--text-heading);
  letter-spacing: -0.01em;
  margin: 0 0 0.5rem;
}

p {
  margin: 0;
  font-size: 1.05rem;
  color: var(--text-secondary);
}

.app-shell {
  max-width: 1100px;
  margin: 0 auto;
  padding: clamp(1.5rem, 4vw, 3rem) clamp(1.25rem, 4vw, 3rem) 4rem;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0;
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in oklab, var(--surface-muted) 85%, white);
  border-bottom: 1px solid var(--border-default);
}

.nav-brand {
  font-weight: 700;
  color: var(--text-heading);
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.95rem;
}

.nav-links a {
  color: var(--link-default);
  font-weight: 600;
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--link-hover);
}

.page-header {
  margin-top: 2rem;
  display: grid;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  background: var(--surface-info-weak);
  color: var(--text-info);
  font-weight: 600;
  font-size: 0.85rem;
  width: fit-content;
}

.metric-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  margin-top: 1rem;
}

.metric {
  background: var(--surface-info-strong);
  border: 1px solid var(--border-info);
  border-radius: 1rem;
  padding: 1rem 1.25rem;
}

.metric-value {
  font-size: clamp(1.4rem, 2.2vw, 2rem);
  color: var(--text-heading);
  font-weight: 700;
}

.metric-label {
  font-size: 0.95rem;
  color: var(--text-info-muted);
  font-weight: 600;
}

.metric-note {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.page {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 2rem;
  padding: 0;
}

.page.single {
  grid-template-columns: minmax(0, 1fr);
}

.panel,
.card {
  background: var(--card-bg);
  border-radius: 1.25rem;
  padding: 1.75rem;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--card-border);
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.action-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.panel-header p {
  max-width: 38ch;
}

.stack {
  display: grid;
  gap: 1.5rem;
}

.home-steps {
  display: grid;
  gap: 1rem;
}

.home-guidance {
  display: grid;
  gap: 1.25rem;
}

.calc-card {
  border: 1px solid var(--border-default);
  border-radius: 1rem;
  padding: 1.1rem 1.2rem;
  background: color-mix(in oklab, var(--surface-muted) 65%, white);
}

.calc-card h3 {
  font-size: 1.15rem;
  margin-bottom: 0.35rem;
}

.calc-card p {
  font-size: 0.98rem;
}

.note-card {
  border-left: 3px solid var(--color-quantum-blue);
}

.note-card h3 {
  margin-bottom: 0.35rem;
  font-size: 1.05rem;
}

@media (min-width: 900px) {
  .home-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .home-guidance {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.bottom-nav {
  margin-top: 4rem;
  border-top: 1px solid var(--border-bottomnav);
  background: var(--surface-bottomnav);
  padding: 2.5rem 0 3rem;
}

.bottom-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.bottom-nav h4 {
  color: var(--text-bottomnav-heading);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 0.75rem;
}

.bottom-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.5rem;
  color: var(--text-bottomnav-body);
  font-size: 0.9rem;
}

.bottom-nav p {
  color: var(--text-bottomnav-body);
  font-size: 0.9rem;
}

.bottom-nav a {
  color: inherit;
  text-decoration: none;
}

.bottom-nav a:hover {
  color: var(--text-link-hover);
  text-decoration: underline;
}

.powered-label {
  margin-top: 0.75rem;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-bottomnav-body);
}

.qds-logo {
  margin-top: 0.5rem;
  height: 32px;
  width: auto;
  object-fit: contain;
}

.site-footer {
  border-top: 1px solid var(--border-section);
  background: var(--surface-footer);
  padding: 1.5rem 0;
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.form-section {
  display: grid;
  gap: 1rem;
}

.form-section h3 {
  font-size: 1.15rem;
}

.attribute-groups {
  display: grid;
  gap: 1rem;
}

.attribute-group {
  border: 1px solid var(--border-default);
  border-radius: 1rem;
  padding: 1rem;
  background: var(--surface-muted);
}

.attribute-group h4 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
  color: var(--text-strong);
}

.attribute-group .stack + .stack {
  margin-top: 1rem;
}

.attribute-options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--border-default);
  background: #ffffff;
  font-size: 0.85rem;
  cursor: pointer;
  transition: border var(--transition-normal), box-shadow var(--transition-normal), background var(--transition-normal);
}

.chip input {
  accent-color: var(--color-quantum-blue);
}

.chip:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-card-hover);
}

.field-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.field {
  display: grid;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-strong);
}

.field input,
.field select {
  padding: 0.75rem 0.9rem;
  border-radius: 0.85rem;
  border: 1px solid var(--border-default);
  background: #ffffff;
  font-size: 0.95rem;
  font-family: inherit;
  min-height: 48px;
  height: 48px;
  line-height: 1.2;
}

.field select {
  appearance: none;
  -webkit-appearance: none;
}

.field input:focus,
.field select:focus {
  outline: none;
  border-color: var(--color-quantum-blue);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-quantum-blue) 18%, transparent);
}

.form-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.status {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: 999px;
  padding: 0.6rem 1.2rem;
  font-weight: 600;
  font-size: 0.95rem;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), background var(--transition-normal);
}

.btn.primary {
  background: var(--button-primary-bg);
  color: var(--button-primary-text);
  box-shadow: var(--shadow-control);
}

.btn.primary:hover {
  background: var(--button-primary-hover-bg);
  transform: translateY(-1px);
}

.btn.secondary {
  background: var(--button-secondary-bg);
  color: var(--button-secondary-text);
}

.btn.secondary:hover {
  background: var(--button-secondary-hover-bg);
  color: var(--text-inverse);
}

.results-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.segment-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 1.5rem 0 0.75rem;
}

.model-card {
  display: grid;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.model-card h3 {
  margin-bottom: 0.35rem;
}

.model-metrics {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.tree-shell {
  border: 1px dashed var(--border-default);
  border-radius: 1rem;
  padding: 2rem;
  background: #ffffff;
  min-height: 420px;
  height: 520px;
  overflow: hidden;
}

.tree-viewport {
  width: 100%;
  height: 100%;
  overflow: auto;
  cursor: grab;
}

.tree-viewport.dragging {
  cursor: grabbing;
  user-select: none;
}

.tree-svg {
  display: block;
}

.tree-link {
  stroke: var(--border-default);
  stroke-width: 2;
  fill: none;
}

.tree-node rect {
  fill: #ffffff;
  stroke: var(--border-default);
  stroke-width: 1.5;
  rx: 12;
}

.tree-node.leaf rect {
  stroke: var(--color-quantum-blue);
  stroke-width: 2;
}

.tree-node text {
  font-family: var(--font-sans);
  fill: var(--text-primary);
  font-size: 12px;
}

.tree-node .node-title {
  font-weight: 700;
  fill: var(--text-heading);
}

.tree-node .node-subtitle {
  font-weight: 600;
  fill: var(--text-strong);
  font-size: 12px;
}

.tree-node .node-detail {
  font-size: 11px;
  fill: var(--text-secondary);
}

.tree-zoom-control {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.tree-zoom-control input {
  accent-color: var(--color-quantum-blue);
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
}

.legend-swatch {
  width: 14px;
  height: 14px;
  border-radius: 4px;
  border: 1px solid var(--border-default);
  background: var(--surface-default);
}

.legend-swatch.legend-target {
  border-color: var(--status-success);
  box-shadow: 0 0 0 2px color-mix(in oklab, var(--status-success) 25%, transparent);
}

.segment-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.segment-card {
  border-radius: 1rem;
  padding: 1.1rem;
  border: 1px solid var(--border-default);
  background: var(--surface-default);
  box-shadow: var(--shadow-card);
  display: grid;
  gap: 0.6rem;
  animation: revealIn 0.7s ease-out both;
}

.segment-card.target {
  border-color: var(--status-success);
  box-shadow: 0 8px 18px rgba(4, 124, 116, 0.18);
}

.segment-card h4 {
  margin: 0;
  color: var(--text-strong);
}

.segment-card .meta {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.segment-card .value {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-heading);
}

.segment-card ul {
  margin: 0;
  padding-left: 1rem;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

.distribution-controls {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: minmax(220px, 280px) minmax(0, 1fr);
  align-items: end;
  margin-bottom: 1.5rem;
}

.distribution-meta {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
}

.distribution-table {
  display: grid;
  gap: 0.5rem;
}

.distribution-row {
  display: grid;
  align-items: center;
  gap: 1rem;
  grid-template-columns: minmax(140px, 1fr) minmax(160px, 2.4fr) minmax(120px, 0.8fr);
  padding: 0.6rem 0.2rem;
  border-bottom: 1px solid var(--border-default);
}

.distribution-row:last-child {
  border-bottom: none;
}

.distribution-label {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-strong);
}

.distribution-bar {
  height: 10px;
  border-radius: 999px;
  background: color-mix(in oklab, var(--surface-muted) 70%, white);
  border: 1px solid var(--border-default);
  overflow: hidden;
}

.distribution-bar span {
  display: block;
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--color-quantum-blue), var(--fountain-blue));
}

.distribution-count {
  text-align: right;
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
}

.empty-state {
  border: 1px dashed var(--border-default);
  border-radius: 1rem;
  padding: 2rem;
  text-align: center;
  color: var(--text-muted);
}

.reveal {
  animation: revealIn 700ms ease-out both;
}

.delay-1 { animation-delay: 120ms; }
.delay-2 { animation-delay: 240ms; }
.delay-3 { animation-delay: 360ms; }

@keyframes revealIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 980px) {
  .page {
    grid-template-columns: 1fr;
  }

  .distribution-controls {
    grid-template-columns: 1fr;
    align-items: stretch;
  }

  .distribution-row {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }

  .distribution-count {
    text-align: left;
  }
}