/* CSS Custom Properties for Design Tokens */
:root {
  --bg-dark-base: #060913;
  --bg-dark-surface: rgba(10, 17, 30, 0.7);
  --bg-dark-card: rgba(16, 26, 48, 0.55);
  
  --border-color: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(59, 130, 246, 0.15);
  
  --text-primary: #f3f4f6;
  --text-secondary: #9ca3af;
  --text-muted: #4b5563;
  
  --color-blue: #3b82f6;
  --color-purple: #8b5cf6;
  --color-cyan: #06b6d4;
  --color-emerald: #10b981;
  --color-rose: #ef4444;
  --color-amber: #f59e0b;

  --gradient-primary: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --gradient-cyan-blue: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
  --gradient-dark: linear-gradient(180deg, rgba(16, 26, 48, 0.8) 0%, rgba(10, 15, 30, 0.9) 100%);
  --gradient-card-glow: linear-gradient(135deg, rgba(59, 130, 246, 0.15) 0%, rgba(139, 92, 246, 0.05) 100%);

  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.2s ease;
}

/* Reset and Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-dark-base);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  background-image: 
    radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.12) 0px, transparent 50%),
    radial-gradient(at 100% 0%, rgba(139, 92, 246, 0.12) 0px, transparent 50%),
    radial-gradient(at 50% 50%, rgba(6, 182, 212, 0.05) 0px, transparent 60%);
  background-attachment: fixed;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Layout Utilities */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

.section-padding {
  padding: 60px 0;
}

.text-center {
  text-align: center;
}

/* Glassmorphism Panels */
.glass-panel {
  background: var(--bg-dark-surface);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 20px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

/* Section Headers */
.section-header {
  margin-bottom: 60px;
  text-align: center;
}

.section-header h2 {
  font-size: 2.5rem;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #ffffff 30%, #d1d5db 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 700px;
  margin: 0 auto;
}

.badge-tag {
  display: inline-flex;
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: var(--color-blue);
  margin-bottom: 16px;
}

/* Navigation Bar */
.navbar {
  border-bottom: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(6, 9, 19, 0.8);
}

.navbar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 72px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Outfit', sans-serif;
  font-size: 1.25rem;
  font-weight: 800;
  background: linear-gradient(135deg, #fff 0%, var(--color-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-links {
  display: flex;
  gap: 32px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.nav-links a:hover {
  color: #fff;
  transition: var(--transition-fast);
}

/* Nav Toggle Button */
.nav-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 6px;
  padding: 8px;
  z-index: 1100;
}

.hamburger-bar {
  width: 24px;
  height: 2px;
  background-color: var(--text-primary);
  transition: var(--transition-fast);
  border-radius: 2px;
}

/* Active Hamburger Animation */
.nav-toggle.active .hamburger-bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}
.nav-toggle.active .hamburger-bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle.active .hamburger-bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Hero Section */
.hero {
  position: relative;
  padding: 70px 0 50px 0;
  overflow: hidden;
}

.hero-content {
  max-width: 850px;
  margin: 0 auto;
  text-align: center;
}

.hero h1 {
  font-size: 4rem;
  line-height: 1.1;
  font-weight: 800;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #ffffff 20%, #9ca3af 60%, #3b82f6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.3rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  font-weight: 400;
}

.btn-group {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: 'Outfit', sans-serif;
  transition: var(--transition-normal);
  cursor: pointer;
  border: 1px solid transparent;
}

.btn-gradient {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: 0 4px 20px rgba(139, 92, 246, 0.25);
}

.btn-gradient:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(139, 92, 246, 0.45);
}

.btn-outline {
  border-color: var(--border-color);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-primary);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

/* Why This Section */
.why-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.comparison-box {
  background: rgba(220, 38, 38, 0.05);
  border: 1px solid rgba(220, 38, 38, 0.15);
  padding: 24px;
  border-radius: 16px;
  margin-bottom: 20px;
}

.comparison-box.pro {
  background: rgba(16, 185, 129, 0.05);
  border: 1px solid rgba(16, 185, 129, 0.15);
}

.comparison-box h4 {
  font-size: 1.1rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.comparison-box ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Interactive Diagram Section */
.diagram-explorer {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 32px;
  margin-top: 40px;
}

.diagram-viewport {
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow-x: auto;
}

.diagram-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.diagram-node {
  background: var(--bg-dark-card);
  border: 1px solid var(--border-color);
  padding: 12px 18px;
  border-radius: 12px;
  font-size: 0.85rem;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: var(--transition-normal);
  flex: 1;
  min-width: 110px;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.diagram-node:hover {
  border-color: var(--color-blue);
  background: rgba(59, 130, 246, 0.08);
  box-shadow: 0 0 15px rgba(59, 130, 246, 0.2);
}

.diagram-node.active {
  background: var(--gradient-primary);
  border-color: transparent;
  box-shadow: 0 0 20px rgba(139, 92, 246, 0.35);
  color: #fff;
}

.diagram-arrow {
  color: var(--text-muted);
  font-weight: 800;
  user-select: none;
}

.diagram-detail-panel {
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  border-left: 1px solid var(--border-color);
}

.diagram-detail-panel h3 {
  font-size: 1.4rem;
  color: #fff;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 12px;
}

.stage-badge {
  align-self: flex-start;
  padding: 4px 8px;
  font-size: 0.7rem;
  font-weight: 700;
  border-radius: 4px;
}

/* Learning Modules */
.modules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.module-card {
  background: var(--bg-dark-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 28px;
  transition: var(--transition-normal);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.module-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 255, 255, 0.15);
  background: rgba(22, 33, 54, 0.4);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.module-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: rgba(59, 130, 246, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-blue);
  border: 1px solid rgba(59, 130, 246, 0.15);
}

.module-card:nth-child(even) .module-icon {
  background: rgba(139, 92, 246, 0.1);
  color: var(--color-purple);
  border-color: rgba(139, 92, 246, 0.15);
}

.module-card h3 {
  font-size: 1.2rem;
  color: #fff;
}

.module-card p {
  color: var(--text-secondary);
  font-size: 0.88rem;
  line-height: 1.5;
}

/* Simulator Section */
.simulator-layout {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 40px;
  margin-top: 40px;
  padding: 40px;
}

.simulator-controls {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.control-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.btn-selector {
  display: flex;
  background: rgba(10, 15, 30, 0.6);
  border: 1px solid var(--border-color);
  padding: 4px;
  border-radius: 8px;
  gap: 4px;
}

.selector-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 10px;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition-fast);
}

.selector-btn:hover {
  color: #fff;
}

.selector-btn.active {
  background: var(--color-blue);
  color: #fff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.simulator-metrics {
  display: flex;
  flex-direction: column;
  gap: 28px;
  justify-content: center;
}

.metric-bar-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.metric-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
}

.metric-name {
  font-weight: 600;
  color: var(--text-secondary);
}

.metric-val {
  font-weight: 700;
  font-family: 'Fira Code', monospace;
}

.progress-track {
  width: 100%;
  height: 8px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 50%;
  background: var(--gradient-primary);
  border-radius: 4px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Evaluation Section */
.eval-dashboard-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.eval-card {
  background: var(--bg-dark-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  align-items: center;
  text-align: center;
}

.eval-score-ring {
  width: 100px;
  height: 100px;
  position: relative;
}

.ring-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: rgba(255, 255, 255, 0.04);
  stroke-width: 6;
}

.ring-fill {
  fill: none;
  stroke-width: 6;
  stroke-linecap: round;
  stroke-dasharray: 283;
  stroke-dashoffset: 80;
  transition: stroke-dashoffset 0.6s ease;
}

.ring-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 1.3rem;
  font-weight: 700;
  font-family: 'Outfit', sans-serif;
}

/* Production Concerns Section */
.concern-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.concern-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  padding: 24px;
  border-radius: 14px;
  display: flex;
  gap: 16px;
}

.concern-number {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-cyan);
  font-family: 'Outfit', sans-serif;
  line-height: 1;
}

.concern-body h4 {
  font-size: 1.1rem;
  color: #fff;
  margin-bottom: 6px;
}

.concern-body p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* Roadmap Section */
.roadmap-timeline {
  display: flex;
  flex-direction: column;
  gap: 32px;
  position: relative;
  margin-top: 40px;
  padding-left: 20px;
}

.roadmap-timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: var(--border-color);
}

.roadmap-step {
  position: relative;
  padding-left: 32px;
}

.roadmap-dot {
  position: absolute;
  left: 0;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--bg-dark-base);
  border: 3px solid var(--color-blue);
  box-shadow: 0 0 8px var(--color-blue);
}

.roadmap-step.completed .roadmap-dot {
  border-color: var(--color-emerald);
  box-shadow: 0 0 8px var(--color-emerald);
}

.roadmap-step h4 {
  font-size: 1.15rem;
  color: #fff;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.roadmap-step p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Collaboration Area */
.collab-box {
  text-align: center;
  padding: 60px 40px;
  background: radial-gradient(circle at center, rgba(139, 92, 246, 0.08) 0%, transparent 70%);
}

.collab-box h2 {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.collab-box p {
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 32px auto;
  font-size: 1.05rem;
}

/* Footer */
footer {
  border-top: 1px solid var(--border-color);
  padding: 40px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Mobile Responsive Adjustments */
@media (max-width: 992px) {
  .why-grid, .diagram-explorer, .simulator-layout, .concern-list {
    grid-template-columns: 1fr;
  }
  
  .diagram-detail-panel {
    border-left: none;
    border-top: 1px solid var(--border-color);
    padding-top: 32px;
  }
  
  .hero h1 {
    font-size: 2.8rem;
  }
}

@media (max-width: 768px) {
  .eval-dashboard-grid {
    grid-template-columns: 1fr;
  }
  
  .navbar-inner {
    height: 72px;
    padding: 0;
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    width: 100%;
    background: rgba(6, 9, 19, 0.96);
    border-bottom: 1px solid var(--border-color);
    padding: 24px;
    gap: 20px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.5);
    z-index: 999;
  }
  
  .nav-links.show {
    display: flex;
    animation: slideDown 0.25s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  }
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}