:root {
  --bg-primary: #F2F6F8;
  --bg-card: #FFFFFF;
  --bg-elevated: #E8F0F4;
  --text-main: #16202A;
  --text-muted: #4B5D6B;
  --text-light: #6B7D8C;
  --teal-main: #0E7490;
  --teal-dark: #0A566B;
  --teal-soft: #E0F2F7;
  --orange-accent: #EA580C;
  --orange-hover: #C2410C;
  --orange-soft: #FFF1E8;
  --border-line: #CBD8E1;
  --border-strong: #94ACB9;
  --shadow-field: 0 8px 24px -6px rgba(22, 32, 42, 0.08), 0 2px 6px -1px rgba(14, 116, 144, 0.06);
  --radius-sm: 4px;
  --radius-md: 8px;
}

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

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

body {
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(circle at 18% 12%, rgba(14, 116, 144, 0.06) 0%, transparent 45%),
    radial-gradient(circle at 85% 75%, rgba(234, 88, 12, 0.05) 0%, transparent 40%),
    repeating-radial-gradient(circle at 10% 25%, transparent 0, transparent 48px, rgba(14, 116, 144, 0.035) 49px, transparent 50px);
  color: var(--text-main);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Global Hyperlink Consistency (Prominent & Identical Before/After Visited) */
a, a:visited {
  color: var(--orange-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s ease, background-color 0.2s ease, border-color 0.2s ease;
}

a:hover, a:focus {
  color: var(--teal-main);
}

/* Top Expedition Coordinate Bar */
.telemetry-bar {
  background-color: var(--text-main);
  color: #D2E0E8;
  font-size: 0.78rem;
  padding: 6px 0;
  border-bottom: 2px solid var(--teal-main);
  font-family: "Consolas", "SFMono-Regular", monospace;
  letter-spacing: 0.04em;
}

.telemetry-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.telemetry-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.telemetry-dot {
  width: 7px;
  height: 7px;
  background-color: var(--orange-accent);
  border-radius: 50%;
  display: inline-block;
}

/* Header & Navigation */
.site-header {
  background-color: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--border-line);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
}

.brand-logo, .brand-logo:visited {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-main);
}

.brand-logo:hover {
  color: var(--teal-main);
}

.brand-logo svg {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
}

.brand-text-wrap {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: 0.03em;
  color: var(--text-main);
  line-height: 1.15;
}

.brand-coords {
  font-size: 0.7rem;
  font-family: "Consolas", monospace;
  color: var(--teal-main);
  letter-spacing: 0.06em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.main-nav a, .main-nav a:visited {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 600;
  font-size: 0.93rem;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition: all 0.2s ease;
}

.main-nav a:hover, .main-nav a.active {
  color: var(--teal-main);
  background-color: var(--teal-soft);
  border-color: rgba(14, 116, 144, 0.25);
}

.main-nav a.nav-hub-pill, .main-nav a.nav-hub-pill:visited {
  background-color: var(--orange-soft);
  color: var(--orange-accent);
  border: 1px solid rgba(234, 88, 12, 0.35);
  font-weight: 700;
}

.main-nav a.nav-hub-pill:hover {
  background-color: var(--orange-accent);
  color: #FFFFFF;
}

/* Container & Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-line);
}

/* Asymmetrical Expedition Section Header */
.section-header-split {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 28px;
  align-items: end;
  margin-bottom: 44px;
  padding-bottom: 20px;
  border-bottom: 2px solid var(--text-main);
  position: relative;
}

.section-header-split::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 110px;
  height: 4px;
  background-color: var(--orange-accent);
}

.coord-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: "Consolas", monospace;
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--teal-main);
  background-color: var(--teal-soft);
  border: 1px solid rgba(14, 116, 144, 0.3);
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.section-header-split h2 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.25;
}

.section-desc {
  color: var(--text-muted);
  font-size: 0.98rem;
  border-left: 3px solid var(--teal-main);
  padding-left: 16px;
}

/* Hero Section */
.hero-section {
  padding: 64px 0 76px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 44px;
  align-items: center;
}

.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-strong);
  padding: 5px 14px;
  border-radius: var(--radius-sm);
  font-family: "Consolas", monospace;
  font-size: 0.8rem;
  color: var(--text-main);
  margin-bottom: 18px;
  box-shadow: 2px 2px 0px var(--teal-main);
}

.hero-kicker span.elev-num {
  color: var(--orange-accent);
  font-weight: 700;
}

.hero-content h1 {
  font-size: 2.65rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -0.01em;
}

.hero-content h1 .highlight-teal {
  color: var(--teal-main);
  border-bottom: 4px solid rgba(234, 88, 12, 0.35);
}

.hero-subtitle {
  font-size: 1.08rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  max-width: 600px;
}

.hero-metrics-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 30px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-line);
  border-left: 4px solid var(--teal-main);
  padding: 14px 18px;
  border-radius: var(--radius-sm);
}

.metric-item .metric-val {
  font-family: "Consolas", monospace;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-main);
  display: block;
}

.metric-item .metric-lbl {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
}

.btn-primary, .btn-primary:visited {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background-color: var(--orange-accent);
  color: #FFFFFF;
  font-weight: 700;
  font-size: 1.02rem;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 2px solid var(--orange-accent);
  box-shadow: 0 6px 16px rgba(234, 88, 12, 0.25);
  transition: all 0.2s ease;
}

.btn-primary:hover {
  background-color: var(--orange-hover);
  border-color: var(--orange-hover);
  color: #FFFFFF;
  transform: translateY(-2px);
}

.btn-secondary, .btn-secondary:visited {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background-color: var(--bg-card);
  color: var(--teal-main);
  font-weight: 700;
  font-size: 1.02rem;
  padding: 14px 26px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 2px solid var(--teal-main);
  transition: all 0.2s ease;
}

.btn-secondary:hover {
  background-color: var(--teal-main);
  color: #FFFFFF;
  transform: translateY(-2px);
}

/* Field Instrument Frame for Hero SVG */
.hero-visual-frame {
  background-color: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: 16px;
  box-shadow: var(--shadow-field);
  position: relative;
}

.hero-visual-frame::before,
.hero-visual-frame::after {
  content: "+";
  font-family: monospace;
  font-weight: 700;
  color: var(--teal-main);
  position: absolute;
  font-size: 14px;
  line-height: 1;
}

.hero-visual-frame::before {
  top: 6px;
  left: 8px;
}

.hero-visual-frame::after {
  bottom: 6px;
  right: 8px;
}

.frame-top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: "Consolas", monospace;
  font-size: 0.74rem;
  color: var(--text-muted);
  padding-bottom: 10px;
  margin-bottom: 10px;
  border-bottom: 1px dashed var(--border-line);
}

.hero-anim-img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius-sm);
  background-color: #0F1922;
}

/* Field Instrument Cards (Staggered & Structured) */
.staggered-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
  align-items: stretch;
}

.field-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-line);
  border-top: 3px solid var(--teal-main);
  border-radius: var(--radius-sm);
  padding: 28px 24px;
  box-shadow: var(--shadow-field);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.field-card:hover {
  transform: translateY(-4px);
  border-top-color: var(--orange-accent);
}

.staggered-grid-3 .field-card:nth-child(2) {
  transform: translateY(14px);
  border-top-color: var(--orange-accent);
}

.staggered-grid-3 .field-card:nth-child(2):hover {
  transform: translateY(10px);
}

.card-meta-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}

.icon-box {
  width: 48px;
  height: 48px;
  background-color: var(--teal-soft);
  border: 1px solid rgba(14, 116, 144, 0.25);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--teal-main);
}

.icon-box svg {
  width: 26px;
  height: 26px;
}

.elev-tag {
  font-family: "Consolas", monospace;
  font-size: 0.74rem;
  color: var(--text-light);
  background-color: var(--bg-primary);
  padding: 3px 8px;
  border-radius: 3px;
  border: 1px solid var(--border-line);
}

.field-card h3 {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
}

.field-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 16px;
}

.card-spec-foot {
  padding-top: 12px;
  border-top: 1px dashed var(--border-line);
  font-family: "Consolas", monospace;
  font-size: 0.78rem;
  color: var(--teal-main);
  display: flex;
  justify-content: space-between;
}

/* 4-Column Grid for Streaming & AI */
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

/* Pricing Matrix */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
  align-items: stretch;
}

.pricing-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: 32px 26px;
  box-shadow: var(--shadow-field);
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.featured {
  border: 2px solid var(--orange-accent);
  box-shadow: 0 12px 30px -6px rgba(234, 88, 12, 0.16);
}

.expedition-ribbon {
  position: absolute;
  top: -13px;
  right: 20px;
  background-color: var(--orange-accent);
  color: #FFFFFF;
  font-family: "Consolas", monospace;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  letter-spacing: 0.04em;
}

.tier-name {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 6px;
}

.tier-coord {
  font-family: "Consolas", monospace;
  font-size: 0.78rem;
  color: var(--teal-main);
  margin-bottom: 18px;
}

.tier-price {
  font-size: 2.3rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-line);
}

.tier-price span {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.spec-list {
  list-style: none;
  margin-bottom: 28px;
  flex-grow: 1;
}

.spec-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
  font-size: 0.94rem;
  color: var(--text-main);
}

.spec-list li svg {
  width: 18px;
  height: 18px;
  color: var(--teal-main);
  flex-shrink: 0;
  margin-top: 4px;
}

/* FAQ Section */
.faq-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.faq-item {
  background-color: var(--bg-card);
  border: 1px solid var(--border-line);
  border-left: 4px solid var(--teal-main);
  border-radius: var(--radius-sm);
  padding: 24px 28px;
  box-shadow: var(--shadow-field);
}

.faq-item h3 {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.faq-q-tag {
  font-family: "Consolas", monospace;
  font-size: 0.8rem;
  background-color: var(--teal-soft);
  color: var(--teal-main);
  padding: 2px 8px;
  border-radius: 3px;
}

.faq-item p {
  color: var(--text-muted);
  font-size: 0.96rem;
}

/* Testimonials Grid */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.report-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-line);
  border-radius: var(--radius-sm);
  padding: 26px;
  box-shadow: var(--shadow-field);
}

.report-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border-line);
}

.explorer-info strong {
  display: block;
  font-size: 1.02rem;
  color: var(--text-main);
}

.explorer-info span {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Article & Hub Layouts */
.page-hero-banner {
  background-color: var(--bg-card);
  border-bottom: 2px solid var(--border-strong);
  padding: 52px 0;
}

.article-shell {
  max-width: 900px;
  margin: 48px auto;
  background-color: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-top: 4px solid var(--teal-main);
  border-radius: var(--radius-sm);
  padding: 44px 48px;
  box-shadow: var(--shadow-field);
}

.article-meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-family: "Consolas", monospace;
  font-size: 0.82rem;
  color: var(--text-muted);
  background-color: var(--bg-primary);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  margin: 20px 0 32px;
  border-left: 3px solid var(--orange-accent);
}

.article-content h2 {
  font-size: 1.48rem;
  font-weight: 800;
  color: var(--text-main);
  margin: 34px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-line);
}

.article-content h3 {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--teal-dark);
  margin: 24px 0 10px;
}

.article-content p {
  font-size: 1.02rem;
  color: var(--text-main);
  margin-bottom: 18px;
  text-align: justify;
}

.article-content ul, .article-content ol {
  margin: 0 0 20px 22px;
  color: var(--text-main);
}

.article-content li {
  margin-bottom: 8px;
}

.article-callout {
  background-color: var(--teal-soft);
  border-left: 4px solid var(--teal-main);
  padding: 18px 22px;
  margin: 26px 0;
  border-radius: var(--radius-sm);
}

/* Hub Cards */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin: 48px 0;
}

.hub-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-line);
  border-top: 3px solid var(--teal-main);
  border-radius: var(--radius-sm);
  padding: 28px;
  box-shadow: var(--shadow-field);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.hub-card h2, .hub-card h3 {
  font-size: 1.28rem;
  margin: 12px 0;
  line-height: 1.35;
}

.hub-card h2 a, .hub-card h2 a:visited,
.hub-card h3 a, .hub-card h3 a:visited {
  color: var(--text-main);
  text-decoration: none;
}

.hub-card h2 a:hover, .hub-card h3 a:hover {
  color: var(--orange-accent);
}

.read-more-link, .read-more-link:visited {
  font-weight: 700;
  color: var(--orange-accent);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 12px;
}

.read-more-link:hover {
  color: var(--teal-main);
}

/* Footer (Strictly 4 Chinese links) */
.site-footer {
  background-color: var(--text-main);
  color: #FFFFFF;
  padding: 36px 0;
  border-top: 3px solid var(--teal-main);
}

.footer-nav-only {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 36px;
}

.footer-nav-only a, .footer-nav-only a:visited {
  color: #F2F6F8;
  font-size: 0.98rem;
  font-weight: 600;
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(242, 246, 248, 0.2);
}

.footer-nav-only a:hover {
  color: #FFFFFF;
  background-color: var(--orange-accent);
  border-color: var(--orange-accent);
}

/* Responsive Design - Rule 7 Compliant (Navigation NEVER disappears on mobile!) */
@media (max-width: 992px) {
  .hero-grid,
  .section-header-split,
  .staggered-grid-3,
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .staggered-grid-3 .field-card:nth-child(2) {
    transform: none;
  }
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .hub-grid, .testimonials-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .main-nav {
    display: flex;
    width: 100%;
    flex-wrap: wrap;
    gap: 6px;
  }
  .main-nav a, .main-nav a:visited {
    font-size: 0.86rem;
    padding: 7px 11px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-line);
    flex: 1 1 auto;
    text-align: center;
  }
  .hero-content h1 {
    font-size: 2rem;
  }
  .hero-metrics-strip {
    grid-template-columns: 1fr;
  }
  .grid-4 {
    grid-template-columns: 1fr;
  }
  .article-shell {
    padding: 26px 20px;
    margin: 24px 12px;
  }
  .footer-nav-only {
    gap: 14px;
  }
}