/* Base Theme & Variables */
:root {
  --bg-primary: #0a0d14;
  --bg-secondary: #121824;
  --bg-card: rgba(22, 30, 46, 0.7);
  --bg-card-hover: rgba(30, 42, 66, 0.8);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-accent: rgba(56, 189, 248, 0.3);
  
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --accent-cyan: #38bdf8;
  --accent-blue: #6366f1;
  --accent-purple: #a855f7;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Sidebar Navigation */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 280px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 1.5rem 1rem;
  position: fixed;
  height: 100vh;
  overflow-y: auto;
  z-index: 100;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
}

.sidebar-brand .logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: white;
  font-size: 1.2rem;
  box-shadow: 0 4px 12px rgba(56, 189, 248, 0.3);
}

.sidebar-brand-text h1 {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.sidebar-brand-text p {
  font-size: 0.75rem;
  color: var(--accent-cyan);
}

.nav-section-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin: 1.25rem 0 0.5rem 0.5rem;
  font-weight: 600;
}

.nav-menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.75rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

.nav-link.active {
  background: linear-gradient(90deg, rgba(56, 189, 248, 0.15), rgba(99, 102, 241, 0.05));
  color: var(--accent-cyan);
  border-left: 3px solid var(--accent-cyan);
}

/* Main Content Area */
.main-content {
  margin-left: 280px;
  flex: 1;
  padding: 2.5rem 3rem;
  max-width: 1400px;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, rgba(30, 42, 66, 0.4), rgba(18, 24, 36, 0.9));
  border: 1px solid var(--border-accent);
  border-radius: 16px;
  padding: 2.5rem;
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(56, 189, 248, 0.12), transparent 70%);
  pointer-events: none;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  border-radius: 999px;
  color: var(--accent-cyan);
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #ffffff 30%, var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-description {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 850px;
  margin-bottom: 1.5rem;
}

.hero-stats {
  display: flex;
  gap: 2rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

.stat-item h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-cyan);
}

.stat-item p {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Sections */
.section {
  margin-bottom: 4rem;
  scroll-margin-top: 2rem;
}

.section-header {
  margin-bottom: 1.75rem;
}

.section-tag {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-cyan);
  margin-bottom: 0.25rem;
  display: block;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 0.25rem;
}

/* Grid & Cards */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  backdrop-filter: blur(12px);
  transition: all 0.2s ease;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(255, 255, 255, 0.15);
  transform: translateY(-2px);
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card-body {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Tech Badges */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.tech-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.25rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.tech-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
}

.tech-info h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.tech-info p {
  font-size: 0.825rem;
  color: var(--text-secondary);
}

/* Interactive Pipeline Diagram */
.pipeline-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  margin-top: 1.5rem;
}

.pipeline-steps {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.pipeline-node {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.25rem;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.pipeline-node:hover, .pipeline-node.active {
  border-color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.08);
}

.node-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.node-number {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.node-text h4 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.node-text p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.node-details-box {
  background: rgba(10, 13, 20, 0.8);
  border: 1px solid var(--border-accent);
  border-radius: 12px;
  padding: 1.5rem;
  margin-top: 1.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.node-details-box h3 {
  color: var(--accent-cyan);
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
}

/* Math Callout Box */
.math-card {
  background: rgba(18, 24, 36, 0.9);
  border-left: 4px solid var(--accent-cyan);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin: 1rem 0;
}

.math-formula {
  font-family: var(--font-mono);
  background: rgba(0, 0, 0, 0.4);
  padding: 0.75rem 1rem;
  border-radius: 6px;
  color: var(--accent-cyan);
  font-size: 0.95rem;
  margin: 0.5rem 0;
  overflow-x: auto;
}

/* Interactive Simulators */
.simulator-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
}

.slider-group {
  margin-bottom: 1.5rem;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.slider-value {
  color: var(--accent-cyan);
  font-family: var(--font-mono);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent-cyan);
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
  cursor: pointer;
}

.gauge-container {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-top: 1.5rem;
  padding: 1.25rem;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 12px;
}

.alpha-display {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--accent-cyan);
  font-family: var(--font-mono);
}

.progress-bar-bg {
  flex: 1;
  height: 14px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 7px;
  overflow: hidden;
  display: flex;
}

.progress-bar-bm25 {
  height: 100%;
  background: var(--accent-amber);
  transition: width 0.3s ease;
}

.progress-bar-dense {
  height: 100%;
  background: var(--accent-purple);
  transition: width 0.3s ease;
}

/* Code Accordion */
.accordion {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.accordion-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  overflow: hidden;
}

.accordion-header {
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
  font-weight: 600;
  font-size: 0.95rem;
}

.accordion-header:hover {
  background: rgba(255, 255, 255, 0.03);
}

.accordion-title-box {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.accordion-content {
  padding: 0 1.25rem 1.25rem 1.25rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  display: none;
}

.accordion-item.open .accordion-content {
  display: block;
}

.function-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background: rgba(56, 189, 248, 0.1);
  color: var(--accent-cyan);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

/* Code block */
pre code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #e2e8f0;
  display: block;
  background: #0d1117;
  padding: 1rem;
  border-radius: 8px;
  overflow-x: auto;
  border: 1px solid var(--border-color);
}

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.875rem;
}

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

.data-table th {
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

.data-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.highlight-row {
  background: rgba(56, 189, 248, 0.08) !important;
  font-weight: 600;
}

.highlight-row td {
  color: var(--accent-cyan);
}

/* Search Input */
.search-box {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.search-box:focus {
  outline: none;
  border-color: var(--accent-cyan);
}