/* ==========================================================================
   灵动云 (LingdongCloud) - 南极冰芯与极地科考风 (Paleo Ice Core Spec)
   Domain: liangxinyun.mom
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* Color Palette - Paleo Ice Core Spec */
  --bg-frost: #E5ECF0;
  --bg-frost-card: rgba(255, 255, 255, 0.75);
  --bg-frost-glass: rgba(238, 244, 248, 0.85);
  --bg-dark-ice: #0F172A;
  --bg-ice-deep: #0C4A6E;
  
  /* Primary & Accent Colors */
  --primary-ice-blue: #0284C7;
  --primary-ice-cyan: #0EA5E9;
  --primary-light-cyan: #38BDF8;
  --accent-polar-teal: #0D9488;
  --text-dark: #0F172A;
  --text-muted: #475569;
  --text-light-muted: #64748B;
  
  /* Ice Refraction & Borders */
  --ice-border: rgba(255, 255, 255, 0.85);
  --ice-border-dark: rgba(2, 132, 199, 0.15);
  --ice-refraction-light: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(255, 255, 255, 0.3) 100%);
  --ice-refraction-accent: linear-gradient(135deg, rgba(2, 132, 199, 0.12) 0%, rgba(56, 189, 248, 0.04) 100%);

  /* Cleanroom Indicators */
  --status-pure: #10B981;
  --status-active: #0284C7;
  
  /* Typography */
  --font-main: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang SC', sans-serif;
  --font-mono: 'JetBrains Mono', Consolas, Monaco, monospace;
}

/* Custom Tail Wing Mouse Cursor */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  cursor: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%230284C7' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M2 2l20 9-9 3-3 9-7-21z' fill='%23E5ECF0' fill-opacity='0.6'/%3E%3Cline x1='13' y1='14' x2='22' y2='22' stroke='%2338BDF8' stroke-width='1.5'/%3E%3C/svg%3E"), auto;
}

button, a, input, select {
  cursor: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%230EA5E9' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M2 2l20 9-9 3-3 9-7-21z' fill='%230284C7' fill-opacity='0.8'/%3E%3Cline x1='13' y1='14' x2='22' y2='22' stroke='%2338BDF8' stroke-width='2'/%3E%3C/svg%3E"), pointer !important;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-frost);
  color: var(--text-dark);
  font-family: var(--font-main);
  line-height: 1.6;
}

body {
  background: var(--bg-frost);
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(255, 255, 255, 0.8) 0%, transparent 40%),
    radial-gradient(circle at 85% 75%, rgba(2, 132, 199, 0.05) 0%, transparent 50%),
    linear-gradient(to bottom, #EDF3F7 0%, #E5ECF0 50%, #DDE6EC 100%);
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* Background Ice Stratum Ruler Lines */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 32px;
  bottom: 0;
  width: 1px;
  background: repeating-linear-gradient(
    to bottom,
    rgba(2, 132, 199, 0.2) 0px,
    rgba(2, 132, 199, 0.2) 2px,
    transparent 2px,
    transparent 20px
  );
  pointer-events: none;
  z-index: 0;
}

@media (max-width: 768px) {
  body::before { display: none; }
}

/* Layout Containers */
.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* Spec Top Banner - Cleanroom Telemetry Bar */
.telemetry-bar {
  background: rgba(15, 23, 42, 0.92);
  color: #94A3B8;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 8px 0;
  border-bottom: 1px solid rgba(56, 189, 248, 0.3);
  letter-spacing: 0.05em;
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
}

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

.telemetry-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.telemetry-dot {
  width: 6px;
  height: 6px;
  background-color: var(--status-pure);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--status-pure);
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

/* Main Navigation Header */
.main-header {
  background: rgba(229, 236, 240, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--ice-border);
  box-shadow: inset 0 -1px 0 rgba(2, 132, 199, 0.1);
  position: sticky;
  top: 33px;
  z-index: 99;
  transition: all 0.3s ease;
}

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

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

.logo-ice-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, #0284C7 0%, #0369A1 100%);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #FFFFFF;
  font-weight: 700;
  font-family: var(--font-mono);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.6), 0 2px 10px rgba(2, 132, 199, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.4);
}

.brand-info {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--text-dark);
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand-tag {
  font-size: 0.65rem;
  padding: 2px 6px;
  background: rgba(2, 132, 199, 0.1);
  color: var(--primary-ice-blue);
  border-radius: 4px;
  font-family: var(--font-mono);
  border: 1px solid rgba(2, 132, 199, 0.2);
}

.brand-domain {
  font-size: 0.75rem;
  color: var(--text-light-muted);
  font-family: var(--font-mono);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.92rem;
  transition: color 0.2s ease;
  position: relative;
}

.nav-link:hover {
  color: var(--primary-ice-blue);
}

.nav-cta-btn {
  background: linear-gradient(135deg, #0284C7 0%, #0EA5E9 100%);
  color: #FFFFFF;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 10px 22px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.5), 0 4px 12px rgba(2, 132, 199, 0.25);
  transition: all 0.25s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.nav-cta-btn:hover {
  transform: translateY(-1px);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.8), 0 6px 18px rgba(2, 132, 199, 0.35);
  background: linear-gradient(135deg, #0369A1 0%, #0284C7 100%);
}

.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--text-dark);
}

/* Ice Core Card Design - Paleo Ice Core Spec */
.ice-card {
  background: var(--bg-frost-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--ice-border);
  border-radius: 16px;
  position: relative;
  overflow: hidden;
  box-shadow: 
    inset 0 1px 2px rgba(255, 255, 255, 0.9),
    0 10px 30px -10px rgba(2, 132, 199, 0.06);
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.ice-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent 0%, rgba(2, 132, 199, 0.6) 50%, transparent 100%);
  opacity: 0.7;
}

.ice-card:hover {
  border-color: rgba(2, 132, 199, 0.3);
  transform: translateY(-3px);
  box-shadow: 
    inset 0 1px 3px rgba(255, 255, 255, 1),
    0 16px 40px -12px rgba(2, 132, 199, 0.12);
}

/* Stratum Ruler Mark Overlay */
.stratum-ruler {
  position: absolute;
  top: 0;
  bottom: 0;
  right: 12px;
  width: 14px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  pointer-events: none;
  opacity: 0.35;
}

.stratum-tick {
  width: 100%;
  height: 1px;
  background: var(--primary-ice-blue);
}

.stratum-tick.major {
  height: 2px;
  width: 100%;
}

.stratum-depth-label {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  color: var(--primary-ice-blue);
  writing-mode: vertical-rl;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  position: absolute;
  right: 4px;
  top: 20%;
  opacity: 0.4;
}

/* Hero Section */
.hero-section {
  padding: 80px 0 60px;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid var(--ice-border);
  border-radius: 30px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--primary-ice-blue);
  margin-bottom: 24px;
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.8);
}

.hero-title {
  font-size: 2.85rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-dark);
  margin-bottom: 20px;
}

.hero-title span.highlight {
  background: linear-gradient(135deg, #0284C7 0%, #0369A1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.12rem;
  color: var(--text-muted);
  margin-bottom: 32px;
  max-width: 580px;
  line-height: 1.7;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.btn-primary-large {
  background: linear-gradient(135deg, #0284C7 0%, #0EA5E9 100%);
  color: #FFFFFF;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.05rem;
  padding: 16px 36px;
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.6);
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.6), 0 8px 24px rgba(2, 132, 199, 0.3);
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.btn-primary-large:hover {
  transform: translateY(-2px);
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.8), 0 12px 32px rgba(2, 132, 199, 0.4);
}

.btn-secondary-large {
  background: rgba(255, 255, 255, 0.8);
  color: var(--text-dark);
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  padding: 16px 28px;
  border-radius: 12px;
  border: 1px solid var(--ice-border);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.8);
  transition: all 0.3s ease;
}

.btn-secondary-large:hover {
  background: rgba(255, 255, 255, 1);
  color: var(--primary-ice-blue);
  border-color: rgba(2, 132, 199, 0.3);
}

.hero-stats-row {
  display: flex;
  align-items: center;
  gap: 32px;
  padding-top: 24px;
  border-top: 1px solid rgba(2, 132, 199, 0.12);
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-value {
  font-size: 1.6rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--primary-ice-blue);
}

.stat-label {
  font-size: 0.78rem;
  color: var(--text-light-muted);
}

/* Ice Core Visual Stand Card */
.hero-visual-card {
  padding: 24px;
  position: relative;
}

.cleanroom-spec-box {
  background: rgba(15, 23, 42, 0.95);
  border-radius: 12px;
  padding: 20px;
  color: #E2E8F0;
  font-family: var(--font-mono);
  border: 1px solid rgba(56, 189, 248, 0.2);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.1);
}

.spec-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  margin-bottom: 16px;
  font-size: 0.8rem;
  color: #38BDF8;
}

.spec-metrics-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.spec-metric {
  background: rgba(255, 255, 255, 0.05);
  padding: 10px;
  border-radius: 6px;
  border-left: 3px solid #0EA5E9;
}

.spec-metric-title {
  font-size: 0.7rem;
  color: #94A3B8;
  margin-bottom: 4px;
}

.spec-metric-val {
  font-size: 0.95rem;
  font-weight: 600;
  color: #F8FAFC;
}

/* Feature Sections */
.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 50px;
}

.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--primary-ice-blue);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: rgba(2, 132, 199, 0.08);
  padding: 4px 12px;
  border-radius: 4px;
  margin-bottom: 12px;
  border: 1px solid rgba(2, 132, 199, 0.15);
}

.section-title {
  font-size: 2.1rem;
  font-weight: 700;
  color: var(--text-dark);
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
}

/* Pricing Grid */
.pricing-section {
  padding: 80px 0;
}

.pricing-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
}

.tab-btn {
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid var(--ice-border);
  padding: 10px 24px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: all 0.25s ease;
}

.tab-btn.active, .tab-btn:hover {
  background: #FFFFFF;
  color: var(--primary-ice-blue);
  border-color: rgba(2, 132, 199, 0.4);
  box-shadow: 0 4px 12px rgba(2, 132, 199, 0.1);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.pricing-card {
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.pricing-card.popular {
  border: 2px solid var(--primary-ice-blue);
  background: rgba(255, 255, 255, 0.9);
}

.popular-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  background: var(--primary-ice-blue);
  color: #FFFFFF;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 12px;
  font-family: var(--font-mono);
}

.plan-name {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-dark);
}

.plan-desc {
  font-size: 0.85rem;
  color: var(--text-light-muted);
  margin-bottom: 20px;
  min-height: 40px;
}

.plan-price {
  font-family: var(--font-mono);
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--primary-ice-blue);
  margin-bottom: 20px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price span.unit {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--text-muted);
}

.plan-features {
  list-style: none;
  margin-bottom: 30px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.plan-features li {
  font-size: 0.88rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.plan-features li::before {
  content: '✓';
  color: var(--primary-ice-blue);
  font-weight: 700;
}

.btn-card {
  width: 100%;
  text-align: center;
  padding: 12px 0;
  background: rgba(2, 132, 199, 0.08);
  color: var(--primary-ice-blue);
  font-weight: 600;
  border-radius: 8px;
  text-decoration: none;
  border: 1px solid rgba(2, 132, 199, 0.2);
  transition: all 0.25s ease;
}

.btn-card:hover {
  background: var(--primary-ice-blue);
  color: #FFFFFF;
  border-color: var(--primary-ice-blue);
}

/* SEO Articles Section */
.articles-section {
  padding: 80px 0;
  background: rgba(255, 255, 255, 0.3);
  border-top: 1px solid var(--ice-border);
  border-bottom: 1px solid var(--ice-border);
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: 28px;
}

.article-card {
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  font-size: 0.78rem;
  color: var(--text-light-muted);
  font-family: var(--font-mono);
}

.article-tag {
  background: rgba(2, 132, 199, 0.1);
  color: var(--primary-ice-blue);
  padding: 2px 8px;
  border-radius: 4px;
}

.article-title {
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
  color: var(--text-dark);
}

.article-title a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease;
}

.article-title a:hover {
  color: var(--primary-ice-blue);
}

.article-excerpt {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.6;
}

.article-read-btn {
  align-self: flex-start;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--primary-ice-blue);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.article-read-btn:hover {
  text-decoration: underline;
}

/* User Reviews Section (80% Vernacular Slang Style) */
.reviews-section {
  padding: 80px 0;
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.review-card {
  padding: 24px;
}

.review-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.review-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, #0EA5E9 0%, #0369A1 100%);
  color: #FFFFFF;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  border: 1px solid rgba(255, 255, 255, 0.8);
}

.review-author-info {
  display: flex;
  flex-direction: column;
}

.review-name {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-dark);
}

.review-role {
  font-size: 0.75rem;
  color: var(--text-light-muted);
}

.review-stars {
  color: #F59E0B;
  font-size: 0.85rem;
  margin-bottom: 10px;
}

.review-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* FAQ Section */
.faq-section {
  padding: 80px 0;
}

.faq-list {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  padding: 20px 24px;
}

.faq-question {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-dark);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-answer {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-top: 12px;
  line-height: 1.7;
  padding-top: 12px;
  border-top: 1px solid rgba(2, 132, 199, 0.08);
}

/* SEO Content Modal / Article Reader Overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 23, 42, 0.7);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: all 0.3s ease;
  padding: 20px;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-content {
  background: #F8FAFC;
  width: 100%;
  max-width: 900px;
  max-height: 85vh;
  overflow-y: auto;
  border-radius: 16px;
  padding: 40px;
  position: relative;
  border: 1px solid var(--ice-border);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.modal-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: rgba(15, 23, 42, 0.05);
  border: none;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-dark);
  transition: all 0.2s ease;
}

.modal-close:hover {
  background: rgba(2, 132, 199, 0.1);
  color: var(--primary-ice-blue);
}

.article-full-body {
  line-height: 1.8;
  color: #334155;
}

.article-full-body h1, .article-full-body h2, .article-full-body h3 {
  color: var(--text-dark);
  margin: 24px 0 12px;
}

.article-full-body p {
  margin-bottom: 16px;
}

.article-full-body ul, .article-full-body ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.article-cta-box {
  background: rgba(2, 132, 199, 0.06);
  border: 1px solid rgba(2, 132, 199, 0.2);
  border-radius: 12px;
  padding: 20px;
  margin: 30px 0;
  text-align: center;
}

/* Footer & PBN Backlink Pipeline (核心任务 2: 页脚 PBN 权重精准输血管道) */
footer.site-footer {
  background: #0B132B;
  color: #94A3B8;
  padding: 60px 0 30px;
  border-top: 1px solid rgba(56, 189, 248, 0.2);
  margin-top: 60px;
  position: relative;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  font-size: 0.88rem;
  color: #64748B;
  margin-top: 12px;
  line-height: 1.6;
}

.footer-title {
  color: #F8FAFC;
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-links a {
  color: #94A3B8;
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: #38BDF8;
}

/* Low-key PBN Links Area (友情链接 PBN 权重输血) */
.pbn-pipeline-box {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 24px;
  margin-top: 30px;
  text-align: center;
}

.pbn-pipeline-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: #475569;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}

.pbn-links-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px 24px;
}

.pbn-link-item {
  color: #64748B;
  text-decoration: none;
  font-size: 0.78rem;
  transition: color 0.2s ease;
  font-family: var(--font-main);
}

.pbn-link-item:hover {
  color: #38BDF8;
  text-decoration: underline;
}

.footer-copyright {
  text-align: center;
  font-size: 0.78rem;
  color: #475569;
  margin-top: 20px;
  font-family: var(--font-mono);
}

/* Responsive Rules */
@media (max-width: 992px) {
  .hero-grid { grid-template-columns: 1fr; }
  .footer-content { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-menu-toggle { display: block; }
  .hero-title { font-size: 2.1rem; }
  .footer-content { grid-template-columns: 1fr; }
  .modal-content { padding: 24px; }
}