:root {
  --bg-primary: #0a0d14;
  --bg-surface: #121824;
  --bg-surface-elevated: #1a2233;
  --bg-surface-subtle: #151d2c;
  --border-color: #26334d;
  --border-active: #3b82f6;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-amber: #f59e0b;
  --accent-amber-bg: rgba(245, 158, 11, 0.12);
  --accent-teal: #14b8a6;
  --accent-teal-bg: rgba(20, 184, 166, 0.12);
  --accent-rose: #f43f5e;
  --accent-rose-bg: rgba(244, 63, 94, 0.12);
  --accent-indigo: #818cf8;
  --accent-indigo-bg: rgba(129, 140, 248, 0.12);
  --accent-emerald: #10b981;
  --accent-emerald-bg: rgba(16, 185, 129, 0.12);

  --font-serif: "Fraunces", Georgia, serif;
  --font-mono: "IBM Plex Mono", Menlo, monospace;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  --max-w: 1240px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: clip;
}

body {
  font-family: var(--font-sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  background: radial-gradient(circle at 50% 0%, #151f33 0%, #0a0d14 70%);
  min-height: 100vh;
  overflow-x: hidden;
}

/* Header & Top Bar */
.topbar {
  border-bottom: 1px solid var(--border-color);
  background: rgba(10, 13, 20, 0.85);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 1rem 1.5rem;
}

.topbar-content {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.brand {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand a {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 600;
}

.brand a:hover {
  color: var(--accent-indigo);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.lang-switch {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.3rem 0.6rem;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  color: var(--text-primary);
  text-decoration: none;
  border: 1px solid var(--border-color);
  transition: all 0.2s ease;
}

.lang-switch:hover {
  border-color: var(--accent-indigo);
}

/* Hero Section */
.hero {
  max-width: var(--max-w);
  margin: 3.5rem auto 2.5rem;
  padding: 0 1.5rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--accent-indigo-bg);
  color: var(--accent-indigo);
  border: 1px solid rgba(129, 140, 248, 0.3);
  margin-bottom: 1.25rem;
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 4.5vw, 3.8rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: #ffffff;
  margin-bottom: 1.5rem;
  max-width: 980px;
}

.standfirst {
  font-size: clamp(1.1rem, 1.8vw, 1.35rem);
  line-height: 1.6;
  color: var(--text-secondary);
  max-width: 900px;
  margin-bottom: 2rem;
}

/* Key Metrics Strip */
.metrics-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 2.5rem 0;
}

.metric-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: border-color 0.2s ease;
}

.metric-card:hover {
  border-color: var(--border-active);
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.85rem;
  font-weight: 700;
  color: #ffffff;
  line-height: 1.1;
  margin-bottom: 0.35rem;
}

.metric-value.amber { color: var(--accent-amber); }
.metric-value.teal { color: var(--accent-teal); }
.metric-value.rose { color: var(--accent-rose); }
.metric-value.indigo { color: var(--accent-indigo); }

.metric-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.metric-sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 0.4rem;
}

/* Section Shell */
.shell {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem 5rem;
}

.section {
  margin-top: 4.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.section-header {
  margin-bottom: 2rem;
}

.section-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-teal);
  margin-bottom: 0.5rem;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.8vw, 2.3rem);
  font-weight: 600;
  color: #ffffff;
  line-height: 1.25;
  margin-bottom: 0.75rem;
}

.section-lead {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 820px;
}

/* Interactive Box & Container */
.interactive-panel {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  margin: 1.5rem 0;
}

/* Disjoint Patients Generator */
.patient-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

@media (max-width: 820px) {
  .patient-grid {
    grid-template-columns: 1fr;
  }
}

.patient-card {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

.patient-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.75rem;
  margin-bottom: 1rem;
}

.patient-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-weight: 600;
}

.patient-tag.a {
  background: var(--accent-rose-bg);
  color: var(--accent-rose);
  border: 1px solid rgba(244, 63, 94, 0.3);
}

.patient-tag.b {
  background: var(--accent-teal-bg);
  color: var(--accent-teal);
  border: 1px solid rgba(20, 184, 166, 0.3);
}

.symptom-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.symptom-item {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.9rem;
  color: var(--text-primary);
  line-height: 1.4;
}

.symptom-icon {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.15rem 0.35rem;
  border-radius: 3px;
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.overlap-meter {
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: center;
  text-align: center;
}

.overlap-badge {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-emerald);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Control Buttons & Selectors */
.controls-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.25rem;
}

.btn {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.55rem 1.1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-surface-elevated);
  color: var(--text-primary);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.2s ease;
}

.btn:hover {
  border-color: var(--accent-indigo);
  background: #232d42;
}

.btn.primary {
  background: var(--accent-indigo);
  color: #ffffff;
  border-color: var(--accent-indigo);
  font-weight: 600;
}

.btn.primary:hover {
  background: #6366f1;
}

.btn.active {
  border-color: var(--accent-teal);
  background: var(--accent-teal-bg);
  color: var(--accent-teal);
}

/* Simulator Canvas & Sliders */
.sim-container {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 960px) {
  .sim-container {
    grid-template-columns: 1fr;
  }
}

.canvas-wrapper {
  background: #080a0f;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  position: relative;
  overflow: hidden;
  height: 480px;
}

canvas#networkCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

.sim-hud {
  position: absolute;
  top: 1rem;
  left: 1rem;
  pointer-events: none;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.hud-item {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: rgba(18, 24, 36, 0.85);
  backdrop-filter: blur(4px);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  border: 1px solid rgba(38, 51, 77, 0.7);
  color: var(--text-secondary);
}

.sim-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.slider-group {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem;
}

.slider-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
}

.slider-header span:first-child {
  color: var(--text-primary);
  font-weight: 500;
}

.slider-header span:last-child {
  font-family: var(--font-mono);
  color: var(--accent-indigo);
  font-weight: 600;
}

input[type="range"] {
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--border-color);
  outline: none;
  -webkit-appearance: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent-indigo);
  cursor: pointer;
  border: 2px solid #ffffff;
  box-shadow: 0 0 8px rgba(129, 140, 248, 0.5);
}

.intervention-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem;
}

.intervention-title {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  color: var(--accent-amber);
  margin-bottom: 0.75rem;
}

.intervention-grid {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* Comorbidity Matrix */
.matrix-wrapper {
  overflow-x: auto;
  margin-top: 1rem;
}

.matrix-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  min-width: 680px;
}

.matrix-table th,
.matrix-table td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  text-align: left;
}

.matrix-table th {
  background: var(--bg-surface-elevated);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.matrix-table td.center {
  text-align: center;
}

.cell-present {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent-rose);
  box-shadow: 0 0 6px rgba(244, 63, 94, 0.6);
}

.cell-bridge {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 3px;
  background: var(--accent-amber);
  box-shadow: 0 0 8px rgba(245, 158, 11, 0.8);
}

.cell-absent {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--border-color);
}

/* Calibrated Evaluations Cards */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.eval-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.eval-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
  gap: 0.75rem;
}

.eval-title {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: #ffffff;
}

.eval-confidence {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  text-transform: uppercase;
  flex-shrink: 0;
}

.confidence-high {
  background: var(--accent-emerald-bg);
  color: var(--accent-emerald);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.confidence-med {
  background: var(--accent-amber-bg);
  color: var(--accent-amber);
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.eval-body {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin-bottom: 1rem;
}

.eval-footer {
  border-top: 1px solid var(--border-color);
  padding-top: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Guardrails & Limits */
.guardrails-box {
  background: rgba(244, 63, 94, 0.05);
  border: 1px solid rgba(244, 63, 94, 0.25);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-top: 1.5rem;
}

.guardrails-title {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-rose);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.guardrails-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.guardrails-list li {
  position: relative;
  padding-left: 1.25rem;
}

.guardrails-list li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--accent-rose);
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 3rem 1.5rem;
  background: var(--bg-primary);
  margin-top: 4rem;
}

.footer-content {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.25rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--text-primary);
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}