/* ══════════════════════════════════════════════════════
   STYLE.CSS — Pathfinding Algorithm Visualizer
   Modern dark theme, clean and professional
   ══════════════════════════════════════════════════════ */

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-elevated: #1a1a25;
  --bg-hover: #222230;
  --border: #2a2a3a;
  --border-light: #3a3a50;
  --text-primary: #e8e8f0;
  --text-secondary: #a0a0b8;
  --text-muted: #686888;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-dim: rgba(99, 102, 241, 0.1);
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.5);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, system-ui, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* ── Navigation ── */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: 60px;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 15px;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.3px;
}

.nav-brand .logo-icon {
  width: 30px;
  height: 30px;
  background: var(--accent);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: white;
  font-weight: 800;
}

.nav-links {
  display: flex;
  gap: 2px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 500;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--bg-elevated);
}

/* ── Hero ── */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 400px;
  background: radial-gradient(ellipse, rgba(99,102,241,0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 640px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: 20px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.5px;
  margin-bottom: 28px;
}

.hero h1 {
  font-size: clamp(36px, 6vw, 64px);
  font-weight: 800;
  line-height: 1.05;
  margin-bottom: 20px;
  letter-spacing: -1.5px;
}

.hero h1 .accent {
  color: var(--accent);
}

.hero p {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.hero-buttons {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 64px;
}

.hero-stats {
  display: flex;
  gap: 48px;
  justify-content: center;
}

.stat {
  text-align: center;
}

.stat-value {
  font-size: 32px;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -1px;
}

.stat-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-top: 6px;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: var(--transition);
}

.btn-primary {
  background: var(--accent);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--border-light);
  background: var(--bg-hover);
}

.btn-race {
  background: var(--accent);
  color: white;
  padding: 12px 32px;
  font-size: 14px;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-family: inherit;
  transition: var(--transition);
  box-shadow: var(--shadow-md);
}

.btn-race:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-race:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* ── Sections ── */
.section {
  position: relative;
  padding: 100px 24px;
}

.section-alt {
  background: var(--bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--accent);
  margin-bottom: 14px;
}

.section-header h2 {
  font-size: clamp(26px, 3.5vw, 40px);
  font-weight: 800;
  margin-bottom: 14px;
  letter-spacing: -0.5px;
}

.section-header p {
  color: var(--text-secondary);
  max-width: 480px;
  margin: 0 auto;
  font-size: 15px;
  line-height: 1.7;
}

/* ── Cards ── */
.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: var(--transition);
}

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

/* ── Network Graph ── */
.graph-container {
  max-width: 1000px;
  margin: 0 auto;
}

.graph-canvas-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-primary);
  box-shadow: var(--shadow-md);
}

.graph-canvas-wrap canvas {
  display: block;
  width: 100%;
  height: 480px;
}

.graph-legend {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 24px;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 500;
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

/* ── Race Section ── */
.race-container {
  max-width: 1200px;
  margin: 0 auto;
}

.race-controls {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: end;
  justify-content: center;
  margin-bottom: 24px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.control-group label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--text-muted);
}

.control-group select {
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 14px;
  min-width: 220px;
  cursor: pointer;
  transition: var(--transition);
}

.control-group select:focus {
  outline: none;
  border-color: var(--accent);
}

/* Algorithm Selection Checkboxes */
.algo-selection {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 28px;
  padding: 16px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
}

.algo-checkbox {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  transition: var(--transition);
  user-select: none;
}

.algo-checkbox:hover {
  border-color: var(--border-light);
}

.algo-checkbox input {
  display: none;
}

.check-indicator {
  width: 16px;
  height: 16px;
  border: 2px solid;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.algo-checkbox input:checked + .check-indicator {
  background: #ffffff;
  border-color: #ffffff;
}



/* Race Grid */
.race-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: 20px;
}

.race-panel {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  overflow: hidden;
  background: var(--bg-primary);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.race-panel:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--border-light);
}

.race-panel-header {
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 2px solid;
  background: var(--bg-secondary);
}

.race-panel-header h3 {
  font-size: 14px;
  font-weight: 700;
}

.algo-badge {
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.race-panel canvas {
  display: block;
  width: 100%;
  height: auto;
  background: var(--bg-primary);
}

.race-panel-stats {
  padding: 14px 20px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.race-stat {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.race-stat-label {
  color: var(--text-muted);
  font-size: 9px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  font-weight: 700;
}

.race-stat-value {
  color: var(--text-primary);
  font-size: 14px;
  font-weight: 700;
  font-family: ui-monospace, SFMono-Regular, monospace;
}

.race-result {
  margin-top: 28px;
  padding: 28px;
  border-radius: var(--radius-md);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  text-align: center;
  display: none;
  box-shadow: var(--shadow-md);
}

.race-result.show {
  display: block;
  animation: fadeIn 0.4s ease;
}

.race-winner {
  font-size: 20px;
  font-weight: 800;
  margin-bottom: 10px;
}

.race-detail {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

/* ── ML Section ── */
.ml-container {
  max-width: 900px;
  margin: 0 auto;
}

.ml-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 20px;
}

.ml-controls-card {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.ml-chart-wrap {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-primary);
}

.ml-chart-wrap canvas {
  display: block;
  width: 100%;
  height: 320px;
}

.slider-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.slider-group label {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
}

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

.slider-group input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  box-shadow: 0 0 8px rgba(99, 102, 241, 0.4);
}

.ml-prediction-box {
  padding: 20px;
  border-radius: var(--radius-md);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  text-align: center;
}

.ml-prediction-value {
  font-size: 32px;
  font-weight: 800;
  color: var(--accent);
  font-family: ui-monospace, SFMono-Regular, monospace;
  letter-spacing: -1px;
}

.ml-prediction-label {
  font-size: 10px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-top: 6px;
}

.ml-status {
  font-size: 13px;
  color: var(--text-muted);
  text-align: center;
  margin-top: 20px;
  font-family: ui-monospace, SFMono-Regular, monospace;
}

.ml-status.ready {
  color: var(--success);
}

/* ── Benchmark ── */
.benchmark-container {
  max-width: 900px;
  margin: 0 auto;
}

.table-card {
  padding: 0;
  overflow: hidden;
}

.benchmark-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.benchmark-table th {
  padding: 14px 20px;
  text-align: left;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
}

.benchmark-table td {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}

.benchmark-table tr:hover td {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.benchmark-table td:first-child {
  font-weight: 700;
  color: var(--text-primary);
}

.benchmark-table td .complexity {
  font-family: ui-monospace, SFMono-Regular, monospace;
  color: var(--accent);
  font-weight: 700;
  font-size: 13px;
}

.charts-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 24px;
}

.chart-card {
  padding: 20px;
}

.chart-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 16px;
}

/* ── Footer ── */
.footer {
  text-align: center;
  padding: 60px 24px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 13px;
  background: var(--bg-secondary);
}

.footer p:first-child {
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

/* ── Animations ── */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .navbar {
    padding: 0 16px;
  }

  .nav-links {
    display: none;
  }

  .hero {
    padding: 100px 16px 60px;
  }

  .hero-stats {
    gap: 32px;
    flex-wrap: wrap;
  }

  .section {
    padding: 60px 16px;
  }

  .race-controls {
    flex-direction: column;
    align-items: stretch;
  }

  .control-group select {
    width: 100%;
    min-width: unset;
  }

  .algo-selection {
    justify-content: flex-start;
  }

  .race-grid {
    grid-template-columns: 1fr;
  }

  .race-panel-stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .ml-grid {
    grid-template-columns: 1fr;
  }

  .charts-row {
    grid-template-columns: 1fr;
  }
}