/* ==========================================================================
   飞鸟 (Flying Bird) - Precision Grid (Swiss Style System)
   Design Aesthetic: Strict Swiss Grid + Oversized Headings + Thin Dividers 
                    + Minimal Color + Sharp Cards + Strong Alignment
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Variables & Precision Grid Tokens
   -------------------------------------------------------------------------- */
:root {
  /* Colors - Minimalist High Contrast Swiss Palette */
  --bg-dark: #07090e;
  --bg-surface: #0d111a;
  --bg-card: #121724;
  --bg-card-hover: #181f30;
  --bg-glass: rgba(7, 9, 14, 0.88);
  
  --border-color: rgba(255, 255, 255, 0.12);
  --border-color-glow: rgba(255, 255, 255, 0.3);

  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --primary-glow: rgba(59, 130, 246, 0.15);
  --accent-cyan: #38bdf8;
  
  --text-primary: #ffffff;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --success: #10b981;
  --warning: #f59e0b;

  /* Typography - Swiss Precision Hierarchy */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;

  /* Precision Layout Tokens */
  --container-max: 1240px;
  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 6px;
  --radius-pill: 2px; /* Sharp technical tags */
  
  --shadow-sm: none;
  --shadow-card: none;
  --shadow-glow: none;
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

/* --------------------------------------------------------------------------
   2. Reset & Layout Foundations
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  background-color: var(--bg-dark);
  color: var(--text-primary);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  overflow-x: hidden;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  max-width: 100%;
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 40px 40px;
}

a {
  color: var(--text-primary);
  text-decoration: none;
  transition: all var(--transition-fast);
  overflow-wrap: anywhere;
}

a:hover {
  color: var(--primary-hover);
}

img, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

button, input, select, textarea {
  font-family: inherit;
  font-size: inherit;
}

ul, ol {
  list-style: none;
}

/* --------------------------------------------------------------------------
   3. Grid System & Section Layouts
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.section-padding {
  padding-top: 5rem;
  padding-bottom: 5rem;
  border-bottom: 1px solid var(--border-color);
}

@media (min-width: 768px) {
  .section-padding {
    padding-top: 7rem;
    padding-bottom: 7rem;
  }
}

.section-header {
  text-align: left;
  max-width: 850px;
  margin-bottom: 4rem;
  border-left: 3px solid var(--primary);
  padding-left: 1.25rem;
}

.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--primary-hover);
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 900;
  line-height: 1.1;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
  text-transform: uppercase;
}

@media (min-width: 768px) {
  .section-title {
    font-size: 3.25rem;
  }
}

.section-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 700px;
}

.gradient-text {
  color: #ffffff;
  background: none;
  -webkit-text-fill-color: initial;
  border-bottom: 2px solid var(--primary);
}

/* Buttons - Sharp Technical Precision */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.9rem 2rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  white-space: nowrap;
  text-align: center;
}

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

.btn-primary:hover {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
  transform: none;
}

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

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--text-primary);
  transform: none;
}

.btn-sm {
  padding: 0.5rem 1.25rem;
  font-size: 0.85rem;
}

.btn-block {
  width: 100%;
}

/* Sharp Cards with Thin Dividers */
.glass-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2rem;
  transition: border-color var(--transition-fast);
  position: relative;
}

.glass-card:hover {
  border-color: var(--text-primary);
  transform: none;
  box-shadow: none;
}

/* --------------------------------------------------------------------------
   4. Header & Navigation (Precision Swiss Alignment)
   -------------------------------------------------------------------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  height: 76px;
  display: flex;
  align-items: center;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.35rem;
  font-weight: 900;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  text-transform: uppercase;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--text-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--bg-dark);
}

.nav-desktop {
  display: none;
}

@media (min-width: 992px) {
  .nav-desktop {
    display: flex;
    align-items: center;
    gap: 2rem;
  }
}

.nav-link {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: color var(--transition-fast);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Mobile Hamburger */
.hamburger {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 24px;
  height: 18px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1100;
}

@media (min-width: 992px) {
  .hamburger {
    display: none;
  }
}

.hamburger span {
  width: 100%;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 0;
  transition: all var(--transition-fast);
}

.hamburger.is-active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.hamburger.is-active span:nth-child(2) {
  opacity: 0;
}

.hamburger.is-active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

.mobile-menu {
  position: fixed;
  top: 76px;
  left: 0;
  width: 100%;
  height: calc(100vh - 76px);
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 2.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  z-index: 1050;
  overflow-y: auto;
}

.mobile-menu.is-active {
  transform: translateX(0);
}

.mobile-nav-link {
  color: var(--text-primary);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border-color);
}

/* --------------------------------------------------------------------------
   5. Hero Section (Oversized Swiss Headings + Grid Dashboard)
   -------------------------------------------------------------------------- */
.hero {
  position: relative;
  padding-top: 4.5rem;
  padding-bottom: 5.5rem;
  border-bottom: 1px solid var(--border-color);
}

@media (min-width: 992px) {
  .hero {
    padding-top: 6.5rem;
    padding-bottom: 7.5rem;
  }
}

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

@media (min-width: 992px) {
  .hero-grid {
    grid-template-columns: 1.1fr 0.9fr;
    gap: 4rem;
  }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.75rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero-badge .pulse-dot {
  width: 6px;
  height: 6px;
  border-radius: 0;
  background-color: var(--success);
}

.hero-title {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.04em;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
}

@media (min-width: 768px) {
  .hero-title {
    font-size: 4.25rem;
  }
}

.hero-description {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  line-height: 1.7;
  max-width: 620px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
}

.hero-features-list {
  display: flex;
  flex-wrap: wrap;
  gap: 1.75rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
}

.hero-features-list span {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.hero-features-list svg {
  color: var(--primary-hover);
}

/* Swiss Grid Network Dashboard */
.dashboard-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.75rem;
  position: relative;
}

.dashboard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 1.25rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.dashboard-title {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--success);
  font-weight: 700;
  text-transform: uppercase;
}

.nodes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.node-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-info {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.node-flag {
  font-size: 1.1rem;
}

.node-name {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text-primary);
}

.node-ping {
  font-size: 0.8rem;
  color: var(--success);
  font-family: var(--font-mono);
  font-weight: 700;
}

.dash-chart {
  width: 100%;
  height: 90px;
  background: #05070a;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
  position: relative;
  overflow: hidden;
}

.chart-svg {
  width: 100%;
  height: 100%;
}

.chart-wave {
  stroke: var(--text-primary);
  stroke-width: 2;
  fill: none;
}

/* --------------------------------------------------------------------------
   6. Core Advantages (Strict Bento Grid)
   -------------------------------------------------------------------------- */
.bento-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .bento-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.bento-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--transition-fast);
}

.bento-card:hover {
  border-color: var(--text-primary);
  transform: none;
  box-shadow: none;
}

.bento-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  margin-bottom: 1.75rem;
}

.bento-title {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 0.85rem;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.bento-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* --------------------------------------------------------------------------
   7. Global Capabilities (Precision Stat Grid)
   -------------------------------------------------------------------------- */
.nodes-section-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 768px) {
  .nodes-section-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.node-stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2rem 1.5rem;
  text-align: left;
  border-top: 3px solid var(--text-primary);
}

.node-stat-number {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  letter-spacing: -0.04em;
}

.node-stat-label {
  font-size: 0.85rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

/* --------------------------------------------------------------------------
   8. AI & Streaming Scenarios
   -------------------------------------------------------------------------- */
.scenarios-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 992px) {
  .scenarios-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.scenario-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2.25rem 2rem;
}

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

.scenario-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.ai-icon, .stream-icon {
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.scenario-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
}

.scenario-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
  margin-bottom: 1.75rem;
}

.pill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.pill-tag {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-primary);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

/* --------------------------------------------------------------------------
   9. SaaS Pricing (Sharp Technical Table)
   -------------------------------------------------------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

@media (min-width: 992px) {
  .pricing-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2.5rem 2rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: border-color var(--transition-fast);
}

.pricing-card:hover {
  border-color: var(--text-primary);
}

.pricing-card.featured {
  background: var(--bg-surface);
  border: 2px solid var(--text-primary);
}

.badge-featured {
  position: absolute;
  top: -1px;
  right: -1px;
  background: var(--text-primary);
  color: var(--bg-dark);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 800;
  padding: 0.3rem 0.85rem;
  border-radius: 0 0 0 var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.pricing-title {
  font-size: 1.4rem;
  font-weight: 900;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
  text-transform: uppercase;
}

.pricing-price {
  font-size: 2.75rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.25rem;
}

.pricing-price span {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  font-family: var(--font-sans);
}

.pricing-features {
  margin-bottom: 2.25rem;
  flex-grow: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--text-secondary);
  font-size: 0.925rem;
  margin-bottom: 0.9rem;
}

.pricing-features svg {
  color: var(--text-primary);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   10. SEO Articles Cards (Grid Layout)
   -------------------------------------------------------------------------- */
.blog-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .blog-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 992px) {
  .blog-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.blog-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--transition-fast);
}

.blog-card:hover {
  border-color: var(--text-primary);
  transform: none;
  box-shadow: none;
}

.blog-meta {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.blog-tag {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  text-transform: uppercase;
}

.blog-title {
  font-size: 1.2rem;
  font-weight: 800;
  line-height: 1.4;
  margin-bottom: 0.85rem;
}

.blog-title a {
  color: var(--text-primary);
}

.blog-title a:hover {
  color: var(--primary-hover);
}

.blog-excerpt {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1.75rem;
}

.blog-read-more {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-primary);
}

/* --------------------------------------------------------------------------
   11. Testimonials Section (Swiss Quotes)
   -------------------------------------------------------------------------- */
.testimonials-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.testimonial-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2rem;
}

.testimonial-text {
  font-size: 0.975rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.5rem;
}

.testimonial-user {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
}

.user-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  color: var(--bg-dark);
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

.user-name {
  font-size: 0.95rem;
  font-weight: 800;
  color: var(--text-primary);
}

.user-role {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   12. FAQ Accordion (Thin Swiss Dividers)
   -------------------------------------------------------------------------- */
.faq-container {
  max-width: 850px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
}

.faq-item {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item.is-open {
  background: var(--bg-surface);
}

.faq-question {
  width: 100%;
  padding: 1.35rem 1.75rem;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.05rem;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.faq-icon {
  width: 18px;
  height: 18px;
  transition: transform var(--transition-fast);
  color: var(--text-secondary);
  flex-shrink: 0;
}

.faq-item.is-open .faq-icon {
  transform: rotate(180deg);
  color: var(--text-primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
  padding: 0 1.75rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.is-open .faq-answer {
  max-height: 500px;
  padding-bottom: 1.5rem;
}

/* --------------------------------------------------------------------------
   13. Footer (Strict Grid Alignment)
   -------------------------------------------------------------------------- */
.footer {
  background: #040609;
  border-top: 1px solid var(--border-color);
  padding-top: 5rem;
  padding-bottom: 2.5rem;
  color: var(--text-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
  margin-bottom: 4rem;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr repeat(3, 1fr);
  }
}

.footer-brand {
  max-width: 320px;
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 1.25rem;
  line-height: 1.65;
}

.footer-column-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 1.5rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 2.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }
}

.footer-ref-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  align-items: center;
}

.footer-ref-links a {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 4px;
  font-weight: 600;
}

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

/* --------------------------------------------------------------------------
   14. Article Layout
   -------------------------------------------------------------------------- */
.article-header {
  padding-top: 3.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 3rem;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  text-transform: uppercase;
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

.article-title {
  font-size: 2.25rem;
  font-weight: 900;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  letter-spacing: -0.03em;
  text-transform: uppercase;
}

@media (min-width: 768px) {
  .article-title {
    font-size: 3.5rem;
  }
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-secondary);
  max-width: 850px;
  margin: 0 auto;
}

.article-content h2 {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-top: 3rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border-color);
  letter-spacing: -0.02em;
}

.article-content h3 {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-top: 2.25rem;
  margin-bottom: 1rem;
}

.article-content p {
  margin-bottom: 1.5rem;
}

.article-content ul, .article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-content ul {
  list-style: square;
}

.article-content ol {
  list-style: decimal;
}

.article-content li {
  margin-bottom: 0.6rem;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1.75rem;
  margin-bottom: 2.25rem;
  font-size: 0.925rem;
  overflow-x: auto;
  display: block;
}

.article-content th, .article-content td {
  padding: 0.85rem 1.15rem;
  border: 1px solid var(--border-color);
  text-align: left;
}

.article-content th {
  background: var(--bg-surface);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-transform: uppercase;
  font-weight: 700;
}

.article-callout {
  background: var(--bg-surface);
  border-left: 3px solid var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 1.5rem 1.75rem;
  margin-top: 2rem;
  margin-bottom: 2rem;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-left-width: 4px;
}

.related-articles {
  margin-top: 4.5rem;
  padding-top: 3.5rem;
  border-top: 1px solid var(--border-color);
}

/* Reduced Motion Accessibility */
@media (prefers-reduced-motion: reduce) {
  *, ::before, ::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}