/* ==========================================================================
   Local vs Server Explained - Design System & CSS Architecture
   ========================================================================== */

:root {
  /* Color Tokens - Dark Theme Default */
  --bg-primary: #0b0f19;
  --bg-secondary: #131b2e;
  --bg-card: rgba(22, 32, 54, 0.7);
  --bg-card-hover: rgba(31, 45, 76, 0.85);
  --bg-input: rgba(255, 255, 255, 0.05);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-local: #38bdf8;   /* Sky Blue for Local */
  --accent-server: #a855f7;  /* Purple/Pink for Server */
  --accent-green: #10b981;   /* Emerald */
  --accent-amber: #f59e0b;   /* Amber */

  --gradient-local: linear-gradient(135deg, #0284c7 0%, #38bdf8 100%);
  --gradient-server: linear-gradient(135deg, #7c3aed 0%, #c084fc 100%);
  --gradient-main: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #c084fc 100%);
  --gradient-glow: radial-gradient(circle, rgba(56, 189, 248, 0.15) 0%, rgba(168, 85, 247, 0.08) 50%, transparent 100%);

  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(56, 189, 248, 0.4);

  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 30px -5px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.25);

  --font-heading: 'Outfit', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme='light'] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: #ffffff;
  --bg-input: rgba(0, 0, 0, 0.04);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(56, 189, 248, 0.5);

  --shadow-sm: 0 2px 5px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 15px 30px rgba(0, 0, 0, 0.08);
  --shadow-glow: 0 0 20px rgba(56, 189, 248, 0.15);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography & Utilities */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.25;
}

.gradient-text {
  background: var(--gradient-main);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.gradient-local-text {
  background: var(--gradient-local);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.gradient-server-text {
  background: var(--gradient-server);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section-padding {
  padding: 6rem 0;
}

.section-title {
  font-size: 2.35rem;
  text-align: center;
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 660px;
  margin: 0 auto 3.5rem auto;
}

/* Glassmorphism Card */
.glass-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.glass-card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.8rem 1.8rem;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-main);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(56, 189, 248, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(56, 189, 248, 0.5);
  filter: brightness(1.1);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--accent-local);
  transform: translateY(-2px);
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 1.25rem 0;
  transition: all var(--transition-normal);
}

.navbar.scrolled {
  padding: 0.8rem 0;
  background: rgba(11, 15, 25, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
}

[data-theme='light'] .navbar.scrolled {
  background: rgba(248, 250, 252, 0.85);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
}

.logo-icon {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: var(--gradient-main);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.8rem;
  list-style: none;
}

.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--accent-local);
}

.theme-toggle-btn {
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  padding: 0.5rem;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  border-color: var(--accent-local);
  transform: scale(1.05);
}

/* Hero Section */
.hero-section {
  min-height: 92vh;
  display: flex;
  align-items: center;
  padding-top: 7rem;
  position: relative;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  top: 20%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: var(--gradient-glow);
  filter: blur(100px);
  border-radius: 50%;
  z-index: 0;
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3.5rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: 3.2rem;
  margin-bottom: 1.25rem;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.hero-desc {
  font-size: 1.15rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 2.5rem;
}

/* Interactive Hero Split Cards */
.split-preview-box {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

.split-card {
  padding: 1.75rem;
  border-radius: var(--radius-md);
  position: relative;
  overflow: hidden;
  transition: transform var(--transition-normal);
}

.split-card:hover {
  transform: translateY(-6px);
}

.split-card-local {
  background: linear-gradient(160deg, rgba(56, 189, 248, 0.12) 0%, rgba(15, 23, 42, 0.4) 100%);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.split-card-server {
  background: linear-gradient(160deg, rgba(168, 85, 247, 0.12) 0%, rgba(15, 23, 42, 0.4) 100%);
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.card-badge {
  display: inline-block;
  padding: 0.3rem 0.8rem;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.badge-local {
  background: rgba(56, 189, 248, 0.2);
  color: var(--accent-local);
}

.badge-server {
  background: rgba(168, 85, 247, 0.2);
  color: var(--accent-server);
}

/* Analogy Cards */
.analogy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
}

.analogy-card {
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.analogy-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.analogy-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
}

.analogy-comparison-box {
  background: var(--bg-input);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.comp-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: 0.92rem;
}

.comp-tag {
  font-weight: 700;
  font-size: 0.78rem;
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  flex-shrink: 0;
}

/* Comparison Section */
.comp-table-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.comp-card {
  padding: 2rem;
  position: relative;
  overflow: hidden;
}

.comp-card-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

/* Interactive Deployment Simulator */
.simulator-container {
  padding: 2.5rem;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
}

.sim-flow {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  margin: 2.5rem 0;
  position: relative;
}

.sim-node {
  flex: 1;
  background: var(--bg-secondary);
  border: 2px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.75rem 1.25rem;
  text-align: center;
  position: relative;
  transition: all var(--transition-normal);
}

.sim-node.active {
  border-color: var(--accent-local);
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.3);
  transform: scale(1.03);
}

.sim-node.server-node.active {
  border-color: var(--accent-server);
  box-shadow: 0 0 20px rgba(168, 85, 247, 0.3);
}

.sim-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
}

.data-packet {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-local);
  box-shadow: 0 0 12px var(--accent-local);
  position: absolute;
  top: 50%;
  left: 20%;
  transform: translateY(-50%);
  opacity: 0;
}

.data-packet.animating {
  animation: movePacket 2s ease-in-out forwards;
}

@keyframes movePacket {
  0% { left: 22%; opacity: 1; background: var(--accent-local); }
  50% { left: 50%; background: var(--accent-amber); scale: 1.4; }
  100% { left: 78%; opacity: 1; background: var(--accent-server); }
}

/* Quiz Section */
.quiz-card {
  padding: 2.5rem;
  max-width: 780px;
  margin: 0 auto;
}

.quiz-option-btn {
  width: 100%;
  padding: 1.1rem 1.4rem;
  text-align: left;
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.quiz-option-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--accent-local);
  transform: translateX(4px);
}

.quiz-option-btn.correct {
  background: rgba(16, 185, 129, 0.15) !important;
  border-color: var(--accent-green) !important;
  color: #34d399 !important;
}

.quiz-option-btn.wrong {
  background: rgba(239, 68, 68, 0.15) !important;
  border-color: #ef4444 !important;
  color: #fca5a5 !important;
}

/* FAQ Accordion */
.faq-container {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.faq-item {
  border-radius: var(--radius-md);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-header {
  padding: 1.5rem 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-weight: 700;
  font-size: 1.1rem;
  user-select: none;
}

.faq-toggle-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--bg-input);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast);
}

.faq-item.active .faq-toggle-icon {
  transform: rotate(180deg);
  background: rgba(56, 189, 248, 0.2);
  color: var(--accent-local);
}

.faq-body {
  padding: 0 1.75rem 1.5rem 1.75rem;
  color: var(--text-secondary);
  line-height: 1.7;
  display: none;
  font-size: 0.98rem;
}

.faq-item.active .faq-body {
  display: block;
}

/* Toast */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 3000;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.toast {
  padding: 0.9rem 1.4rem;
  border-radius: var(--radius-md);
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border: 1px solid var(--accent-local);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* Responsive */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; text-align: center; }
  .sim-flow { flex-direction: column; gap: 2rem; }
  .sim-arrow { transform: rotate(90deg); }
  .nav-links { display: none; }
}