/* ==========================================================================
   91机场 Technical Blueprint Design System
   Color Palette:
     - White: #FCFDFD
     - Pale Blue-Gray: #EFF4F5
     - Ink: #183139
     - Muted Cyan: #4B8791
     - Fine-line Gray: #C8D6D9
     - Dark Accent: #12242B
   ========================================================================== */

:root {
  --color-bg-white: #FCFDFD;
  --color-bg-surface: #EFF4F5;
  --color-bg-card: #FFFFFF;
  --color-ink: #183139;
  --color-ink-muted: #435B63;
  --color-cyan: #4B8791;
  --color-cyan-hover: #3D6F77;
  --color-cyan-light: #E5EFF1;
  --color-line: #C8D6D9;
  --color-line-dark: #A5B8BD;
  --color-badge-bg: #EAF1F3;
  --color-warning-bg: #FFF9E6;
  --color-warning-border: #E8D38D;
  --color-warning-text: #6B5514;
  
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;

  --container-max: 1200px;
  --container-padding: 1.5rem;
  --header-height: 72px;
  
  --radius-sm: 3px;
  --radius-md: 6px;
  --radius-lg: 8px;
  
  --transition-fast: 0.18s ease;
  --transition-normal: 0.28s ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--color-ink);
  background-color: var(--color-bg-white);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Accessibility: Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-ink);
  color: #FFFFFF;
  padding: 0.75rem 1.25rem;
  z-index: 9999;
  text-decoration: none;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: top var(--transition-fast);
}
.skip-link:focus {
  top: 1rem;
}

/* Focus States */
:focus-visible {
  outline: 2px solid var(--color-cyan);
  outline-offset: 3px;
}

/* Typography Scale */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-ink);
  font-weight: 700;
  line-height: 1.25;
}

h1 {
  font-size: 35px; /* Mobile first */
  letter-spacing: -0.02em;
}

@media (min-width: 992px) {
  h1 {
    font-size: 55px; /* Desktop specification */
    line-height: 1.15;
  }
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

@media (min-width: 992px) {
  h2 {
    font-size: 2.25rem;
  }
}

h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1rem;
  color: var(--color-ink);
}

a {
  color: var(--color-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}
a:hover {
  color: var(--color-cyan-hover);
  text-decoration: underline;
}

img, svg {
  max-width: 100%;
  height: auto;
  vertical-align: middle;
}

ul, ol {
  padding-left: 1.25rem;
  margin-bottom: 1rem;
}

li {
  margin-bottom: 0.35rem;
}

/* Monospace for Technical Labels Only */
.tech-label,
.tech-badge,
.route-tag,
.coord-tag,
.code-inline,
.spec-code,
pre, code {
  font-family: var(--font-mono);
}

.tech-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.2rem 0.55rem;
  background-color: var(--color-badge-bg);
  color: var(--color-ink);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.tech-badge.cyan {
  background-color: var(--color-cyan-light);
  border-color: var(--color-cyan);
  color: var(--color-ink);
}

/* --------------------------------------------------------------------------
   Blueprint Coordinate Grid Pattern (Only in selected areas)
   -------------------------------------------------------------------------- */
.blueprint-grid-area {
  background-color: var(--color-bg-surface);
  background-image:
    linear-gradient(to right, rgba(200, 214, 217, 0.45) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(200, 214, 217, 0.45) 1px, transparent 1px);
  background-size: 28px 28px;
  position: relative;
}

.blueprint-grid-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  position: relative;
}

/* Blueprint Corner Ticks */
.blueprint-corner {
  position: relative;
}
.blueprint-corner::before,
.blueprint-corner::after {
  content: "";
  position: absolute;
  width: 8px;
  height: 8px;
  border-color: var(--color-cyan);
  pointer-events: none;
}
.blueprint-corner::before {
  top: -1px;
  left: -1px;
  border-top: 2px solid var(--color-cyan);
  border-left: 2px solid var(--color-cyan);
}
.blueprint-corner::after {
  bottom: -1px;
  right: -1px;
  border-bottom: 2px solid var(--color-cyan);
  border-right: 2px solid var(--color-cyan);
}

/* --------------------------------------------------------------------------
   Layout & Container
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.section {
  padding-top: 4rem;
  padding-bottom: 4rem;
}

@media (min-width: 992px) {
  .section {
    padding-top: 5.5rem;
    padding-bottom: 5.5rem;
  }
}

.section-bg-surface {
  background-color: var(--color-bg-surface);
}

.section-header {
  margin-bottom: 2.75rem;
  text-align: left;
}

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

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-cyan);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

.section-subtitle {
  font-size: 1.0625rem;
  color: var(--color-ink-muted);
  max-width: 720px;
  margin-top: 0.5rem;
}

.section-header.text-center .section-subtitle {
  margin-left: auto;
  margin-right: auto;
}

/* --------------------------------------------------------------------------
   Buttons & CTAs
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8125rem 1.625rem;
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-ink);
  color: #FFFFFF;
  border-color: var(--color-ink);
}
.btn-primary:hover {
  background-color: var(--color-cyan);
  border-color: var(--color-cyan);
  color: #FFFFFF;
  text-decoration: none;
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-ink);
  border-color: var(--color-line-dark);
}
.btn-secondary:hover {
  background-color: var(--color-bg-surface);
  border-color: var(--color-ink);
  color: var(--color-ink);
  text-decoration: none;
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.8125rem;
}

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
}

/* --------------------------------------------------------------------------
   Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(252, 253, 253, 0.94);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-line);
  height: var(--header-height);
  display: flex;
  align-items: center;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-ink);
  text-decoration: none;
}
.brand-logo:hover {
  text-decoration: none;
}

.brand-icon {
  width: 28px;
  height: 28px;
  color: var(--color-cyan);
}

.nav-menu {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 1.5rem;
  align-items: center;
}

.nav-link {
  color: var(--color-ink);
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 0.35rem 0.2rem;
  position: relative;
  text-decoration: none;
}
.nav-link:hover,
.nav-link.active {
  color: var(--color-cyan);
  text-decoration: none;
}

.nav-cta-group {
  display: none;
  align-items: center;
  gap: 0.75rem;
}

/* Hamburger Button */
.menu-toggle {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  width: 32px;
  height: 32px;
  background: transparent;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 6px;
  cursor: pointer;
  z-index: 1010;
}
.menu-toggle span {
  width: 100%;
  height: 2px;
  background-color: var(--color-ink);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* Hamburger Opened State */
.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* Mobile Drawer */
.mobile-nav-drawer {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  height: calc(100vh - var(--header-height));
  background-color: var(--color-bg-white);
  border-bottom: 1px solid var(--color-line);
  padding: 2rem var(--container-padding);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  transform: translateY(-100%);
  opacity: 0;
  visibility: hidden;
  transition: transform var(--transition-normal), opacity var(--transition-normal), visibility var(--transition-normal);
  overflow-y: auto;
  z-index: 999;
}
.mobile-nav-drawer.open {
  transform: translateY(0);
  opacity: 1;
  visibility: visible;
}

.mobile-nav-list {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.mobile-nav-link {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-ink);
  display: block;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-line);
}
.mobile-nav-link:hover {
  color: var(--color-cyan);
  text-decoration: none;
}

@media (min-width: 992px) {
  .menu-toggle {
    display: none;
  }
  .nav-menu {
    display: flex;
  }
  .nav-cta-group {
    display: flex;
  }
  .mobile-nav-drawer {
    display: none !important;
  }
}

/* --------------------------------------------------------------------------
   Hero Section: Split Layout (Left copy, Right SVG/CSS schematic)
   -------------------------------------------------------------------------- */
.hero-section {
  position: relative;
  padding-top: 3rem;
  padding-bottom: 3.5rem;
  border-bottom: 1px solid var(--color-line);
}

@media (min-width: 992px) {
  .hero-section {
    padding-top: 4.5rem;
    padding-bottom: 5.5rem;
  }
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  align-items: center;
}

@media (min-width: 992px) {
  .hero-grid {
    grid-template-columns: 1.15fr 1fr;
    gap: 3.5rem;
  }
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.hero-desc {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--color-ink-muted);
  max-width: 580px;
  margin-bottom: 0.5rem;
}

.hero-meta-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  align-items: center;
  margin-top: 0.5rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--color-line);
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
}
.hero-meta-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.hero-meta-item svg {
  color: var(--color-cyan);
}

/* Blueprint Network Schematic Dashboard */
.schematic-wrapper {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(24, 49, 57, 0.04);
}

.schematic-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 0.75rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--color-line);
  font-size: 0.75rem;
  color: var(--color-ink-muted);
}

.schematic-indicators {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #2E8540;
}
.status-dot.pulse {
  animation: pulse-green 2s infinite ease-in-out;
}
@keyframes pulse-green {
  0% { transform: scale(0.9); opacity: 0.7; }
  50% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.7; }
}

.schematic-svg-container {
  width: 100%;
  aspect-ratio: 16 / 10;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #FCFDFD;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
  position: relative;
}

/* SVG Route Line Animation (draws once when visible, respects reduced motion) */
.route-line-animated {
  stroke-dasharray: 600;
  stroke-dashoffset: 600;
  animation: drawLine 2.2s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes drawLine {
  to {
    stroke-dashoffset: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .route-line-animated {
    stroke-dashoffset: 0 !important;
    animation: none !important;
  }
  .status-dot.pulse {
    animation: none !important;
  }
}

.schematic-annotations {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-line);
}

.annotation-item {
  font-size: 0.75rem;
  line-height: 1.4;
  color: var(--color-ink-muted);
  display: flex;
  gap: 0.4rem;
}

.annotation-num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-cyan);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   Core Benefits Section (3 Columns)
   -------------------------------------------------------------------------- */
.benefits-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

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

.benefit-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  position: relative;
  display: flex;
  flex-direction: column;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

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

.benefit-index {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-cyan);
  margin-bottom: 0.75rem;
}

.benefit-icon-box {
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg-surface);
  color: var(--color-ink);
  margin-bottom: 1.25rem;
}

/* --------------------------------------------------------------------------
   Split-Layout Advantages Area
   -------------------------------------------------------------------------- */
.advantages-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  align-items: center;
}

@media (min-width: 992px) {
  .advantages-split {
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
  }
}

.advantages-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.advantage-item {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-line);
}
.advantage-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.adv-step-num {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-cyan);
  background-color: var(--color-cyan-light);
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.adv-content h4 {
  font-size: 1.125rem;
  margin-bottom: 0.35rem;
}

.adv-content p {
  font-size: 0.9375rem;
  color: var(--color-ink-muted);
  margin: 0;
}

.adv-diagram-panel {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}

/* --------------------------------------------------------------------------
   Global Nodes Topology Section
   -------------------------------------------------------------------------- */
.nodes-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

@media (min-width: 600px) {
  .nodes-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 992px) {
  .nodes-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.node-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: border-color var(--transition-fast);
}

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

.node-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-region {
  font-weight: 700;
  font-size: 1.0625rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.node-specs {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
  padding-top: 0.5rem;
  border-top: 1px dashed var(--color-line);
}

.node-spec-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.editorial-note {
  background-color: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  color: var(--color-warning-text);
  font-size: 0.8125rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  margin-top: 1.5rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}

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

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

.scenario-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}

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

.scenario-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background-color: var(--color-cyan-light);
  color: var(--color-cyan-hover);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.app-pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.app-pill {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  color: var(--color-ink);
}

/* --------------------------------------------------------------------------
   Pricing Section (Clear Rows)
   -------------------------------------------------------------------------- */
.pricing-container {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.pricing-row {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  align-items: center;
  transition: border-color var(--transition-fast);
}

@media (min-width: 768px) {
  .pricing-row {
    grid-template-columns: 1.5fr 2fr 1fr;
    padding: 1.75rem 2rem;
  }
}

.pricing-row.featured {
  border-color: var(--color-cyan);
  background-color: #FAFCFC;
  box-shadow: 0 4px 16px rgba(75, 135, 145, 0.08);
}

.pricing-info h3 {
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.35rem;
}

.pricing-tagline {
  font-size: 0.875rem;
  color: var(--color-ink-muted);
  margin: 0;
}

.pricing-features-list {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.875rem;
}

.pricing-feature-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-ink);
}

.pricing-feature-item svg {
  color: var(--color-cyan);
  flex-shrink: 0;
}

.pricing-action {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.5rem;
}

@media (min-width: 768px) {
  .pricing-action {
    align-items: flex-end;
  }
}

.pricing-placeholder-tag {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-warning-text);
  background-color: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  display: inline-block;
  margin-bottom: 0.4rem;
}

/* --------------------------------------------------------------------------
   SEO Articles Section (9 Cards: 3 col desktop, 2 col tablet, 1 col mobile)
   Directly below Pricing
   -------------------------------------------------------------------------- */
.articles-grid {
  display: grid;
  grid-template-columns: 1fr; /* 1 col mobile */
  gap: 1.5rem;
}

@media (min-width: 640px) {
  .articles-grid {
    grid-template-columns: repeat(2, 1fr); /* 2 col tablet */
  }
}

@media (min-width: 1024px) {
  .articles-grid {
    grid-template-columns: repeat(3, 1fr); /* 3 col desktop */
  }
}

.article-doc-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  height: 100%;
  position: relative;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.article-doc-card:hover {
  border-color: var(--color-cyan);
  transform: translateY(-2px);
}

.doc-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.doc-index {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-cyan);
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-sm);
}

.doc-card-title {
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.5rem;
}

.doc-card-title a {
  color: var(--color-ink);
  text-decoration: none;
}
.doc-card-title a:hover {
  color: var(--color-cyan);
}

.doc-card-excerpt {
  font-size: 0.875rem;
  color: var(--color-ink-muted);
  line-height: 1.55;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.doc-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 0.75rem;
  border-top: 1px dashed var(--color-line);
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
}

.doc-read-link {
  font-weight: 600;
  color: var(--color-cyan);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}
.doc-read-link:hover {
  color: var(--color-cyan-hover);
}

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

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

.testimonial-card {
  background-color: var(--color-bg-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.testimonial-quote {
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--color-ink);
  margin-bottom: 1.25rem;
  position: relative;
  font-style: italic;
}

.testimonial-author {
  display: flex;
  flex-direction: column;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-line);
}

.author-name {
  font-weight: 700;
  font-size: 0.9375rem;
}

.author-role {
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
}

.sample-marker {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--color-cyan);
  background: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  padding: 0.1rem 0.35rem;
  border-radius: var(--radius-sm);
  display: inline-block;
  margin-top: 0.4rem;
  align-self: flex-start;
}

/* --------------------------------------------------------------------------
   Accessible FAQ Section
   -------------------------------------------------------------------------- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 860px;
  margin: 0 auto;
}

.faq-item {
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-white);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 1.25rem 1.5rem;
  background: transparent;
  border: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  text-align: left;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--color-ink);
  font-family: var(--font-sans);
}

.faq-question:hover {
  background-color: var(--color-bg-surface);
}

.faq-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: var(--color-cyan);
  transition: transform var(--transition-fast);
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  display: none;
  padding: 0 1.5rem 1.25rem 1.5rem;
  font-size: 0.9375rem;
  color: var(--color-ink-muted);
  line-height: 1.65;
}

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

/* --------------------------------------------------------------------------
   Footer Section
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: #12242B;
  color: #C8D6D9;
  padding-top: 4rem;
  padding-bottom: 2.5rem;
  border-top: 1px solid var(--color-ink);
  font-size: 0.875rem;
}

.site-footer a {
  color: #C8D6D9;
  text-decoration: none;
}
.site-footer a:hover {
  color: #FFFFFF;
  text-decoration: underline;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  margin-bottom: 3rem;
}

@media (min-width: 600px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: #FFFFFF;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-desc {
  color: #8CA3A9;
  line-height: 1.6;
  max-width: 320px;
}

.footer-col-title {
  color: #FFFFFF;
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-family: var(--font-mono);
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid rgba(200, 214, 217, 0.15);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-items: center;
  text-align: center;
  color: #8CA3A9;
  font-size: 0.8125rem;
}

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

/* --------------------------------------------------------------------------
   Article & Single Page Content Layout
   -------------------------------------------------------------------------- */
.article-header-area {
  padding: 3rem 0 2rem 0;
  border-bottom: 1px solid var(--color-line);
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
  margin-bottom: 1rem;
}

.breadcrumb-nav a {
  color: var(--color-ink-muted);
}
.breadcrumb-nav a:hover {
  color: var(--color-cyan);
}
.breadcrumb-separator {
  color: var(--color-line-dark);
}

.article-meta-info {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--color-line);
}

.article-body-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  padding-top: 2.5rem;
  padding-bottom: 4rem;
}

@media (min-width: 992px) {
  .article-body-layout {
    grid-template-columns: 3fr 1fr;
    gap: 3.5rem;
  }
}

.article-content {
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--color-ink);
}

.article-content h2 {
  font-size: 1.625rem;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-line);
}

.article-content h3 {
  font-size: 1.25rem;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.article-content pre {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 1rem;
  overflow-x: auto;
  font-size: 0.875rem;
  margin: 1.25rem 0;
}

.article-content code {
  font-size: 0.9em;
  background-color: var(--color-bg-surface);
  padding: 0.15rem 0.35rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-line);
}

.article-content pre code {
  background-color: transparent;
  padding: 0;
  border: none;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9375rem;
}

.article-content th,
.article-content td {
  border: 1px solid var(--color-line);
  padding: 0.75rem 1rem;
  text-align: left;
}

.article-content th {
  background-color: var(--color-bg-surface);
  font-weight: 700;
}

.article-content tr:nth-child(even) td {
  background-color: #FAFCFC;
}

.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.sidebar-widget {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

.sidebar-widget-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-line);
}

.related-links-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  font-size: 0.875rem;
}

/* Callout Box */
.callout-box {
  background-color: var(--color-cyan-light);
  border-left: 4px solid var(--color-cyan);
  padding: 1.25rem;
  margin: 1.5rem 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.callout-box p:last-child {
  margin-bottom: 0;
}