/* 
  星链机场 - Linear / Vercel Style Minimal Light CSS
  Background: #FAFAFA | Text: #0A0A0A | Border: #E5E5E5 | Accent: #4F46E5
*/

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

:root {
  --bg-color: #FAFAFA;
  --text-primary: #0A0A0A;
  --text-secondary: #525252;
  --text-muted: #737373;
  --border-color: #E5E5E5;
  --accent-color: #4F46E5;
  --accent-hover: #4338CA;
  --accent-light: #EEF2FF;
  --card-bg: #FFFFFF;
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --container-width: 1120px;
  --transition-fast: 150ms ease;
  --soft-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.07), 0 4px 6px -2px rgba(0, 0, 0, 0.03);
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-color);
  color: var(--text-primary);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  letter-spacing: -0.02em;
  font-weight: 700;
  line-height: 1.25;
}

p {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.7;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(250, 250, 250, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background-color: #0A0A0A;
  color: #FFFFFF;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-link {
  position: relative;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 0;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: width var(--transition-fast);
}

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

.nav-link:hover::after {
  width: 100%;
}

.nav-highlight {
  color: var(--accent-color) !important;
  font-weight: 600;
}

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

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-color);
  padding: 8px;
  border-radius: 6px;
  cursor: pointer;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 10px 20px;
  border-radius: 6px;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-primary {
  background-color: #0A0A0A;
  color: #FFFFFF;
  border-color: #0A0A0A;
}

.btn-primary:hover {
  background-color: #262626;
  border-color: #262626;
  color: #FFFFFF;
}

.btn-accent {
  background-color: var(--accent-color);
  color: #FFFFFF;
  border-color: var(--accent-color);
}

.btn-accent:hover {
  background-color: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #FFFFFF;
}

.btn-secondary {
  background-color: #FFFFFF;
  color: var(--text-primary);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: #F5F5F5;
  border-color: #D4D4D4;
}

.btn-sm {
  padding: 7px 14px;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 13px 26px;
  font-size: 1rem;
}

/* Hero Section */
.hero-section {
  padding: 64px 0 56px;
  border-bottom: 1px solid var(--border-color);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.hero-copy {
  text-align: left;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  border-radius: 9999px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #10B981;
}

.hero-headline {
  font-size: clamp(2.3rem, 4.5vw, 3.5rem); /* up to 56px */
  line-height: 1.15;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.hero-subcopy {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 540px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.hero-features-list {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.hero-features-list span {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Dashboard Mockup Card */
.dashboard-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 24px;
  box-shadow: var(--soft-shadow);
}

.dashboard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 20px;
}

.dashboard-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  font-weight: 600;
}

.pulse-indicator {
  width: 10px;
  height: 10px;
  background-color: #10B981;
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

.speed-metric {
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.speed-metric strong {
  font-size: 1.15rem;
  color: var(--accent-color);
  font-weight: 700;
}

.node-list-preview {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 20px;
}

.node-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background-color: #FAFAFA;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 0.85rem;
  transition: background-color var(--transition-fast);
}

.node-row.active {
  background-color: var(--accent-light);
  border-color: rgba(79, 70, 229, 0.3);
}

.node-meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.flag {
  font-size: 1.1rem;
}

.node-ping {
  font-family: monospace;
  font-size: 0.8rem;
  color: #059669;
  font-weight: 600;
}

.chart-container {
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
}

.chart-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

/* Trust Strip */
.trust-strip {
  padding: 32px 0;
  border-bottom: 1px solid var(--border-color);
  background-color: #FFFFFF;
}

.trust-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.trust-item h4 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.trust-item p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Section Header */
.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 48px;
}

.section-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-color);
  margin-bottom: 12px;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 16px;
}

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

/* Features (3 columns) */
.features-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-color);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 32px 28px;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-2px);
  border-color: #D4D4D4;
}

.feature-icon-box {
  width: 44px;
  height: 44px;
  border-radius: 8px;
  background-color: #FAFAFA;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-color);
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* Streaming & AI Cards */
.unlock-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-color);
  background-color: #FFFFFF;
}

.unlock-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.unlock-card {
  background-color: #FAFAFA;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 24px 20px;
  text-align: center;
  transition: all var(--transition-fast);
}

.unlock-card:hover {
  background-color: #FFFFFF;
  border-color: var(--accent-color);
}

.unlock-icon-badge {
  width: 48px;
  height: 48px;
  margin: 0 auto 16px;
  border-radius: 10px;
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  font-weight: 700;
}

.unlock-card h4 {
  font-size: 1.05rem;
  margin-bottom: 8px;
}

.unlock-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Latency Comparison */
.latency-section {
  padding: 64px 0;
  border-bottom: 1px solid var(--border-color);
}

.latency-container {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 36px 40px;
  max-width: 860px;
  margin: 0 auto;
}

.latency-row {
  margin-bottom: 24px;
}

.latency-row:last-child {
  margin-bottom: 0;
}

.latency-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.latency-bar-track {
  height: 14px;
  background-color: #F5F5F5;
  border-radius: 7px;
  overflow: hidden;
}

.latency-bar-fill {
  height: 100%;
  border-radius: 7px;
  transition: width 1s cubic-bezier(0.16, 1, 0.3, 1);
}

.latency-bar-xinglian {
  background-color: var(--accent-color);
  width: 14%;
}

.latency-bar-average {
  background-color: #D4D4D4;
  width: 85%;
}

/* Pricing Table */
.pricing-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-color);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.featured {
  border-top: 3px solid var(--accent-color);
  box-shadow: var(--soft-shadow);
}

.featured-badge {
  position: absolute;
  top: -12px;
  right: 24px;
  background-color: var(--accent-color);
  color: #FFFFFF;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 9999px;
  text-transform: uppercase;
}

.pricing-header {
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-color);
}

.plan-name {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.plan-price-box {
  display: flex;
  align-items: baseline;
  margin: 16px 0;
}

.currency {
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--text-primary);
}

.amount {
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--text-primary);
}

.period {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-left: 6px;
}

.pricing-features {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.pricing-features li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.pricing-features li svg {
  flex-shrink: 0;
  color: #10B981;
}

.pricing-features li.dimmed {
  color: #A3A3A3;
}

.pricing-features li.dimmed svg {
  color: #D4D4D4;
}

/* Extra Pricing Info Bar */
.pricing-extra-note {
  margin-top: 36px;
  text-align: center;
  font-size: 0.88rem;
  color: var(--text-muted);
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 16px 20px;
}

/* User Reviews */
.reviews-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-color);
  background-color: #FFFFFF;
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background-color: #FAFAFA;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: #F59E0B;
  display: flex;
  gap: 3px;
  margin-bottom: 14px;
}

.review-text {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 20px;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.author-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: #E0E7FF;
  color: var(--accent-color);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.88rem;
}

.author-info h5 {
  font-size: 0.9rem;
  margin-bottom: 2px;
}

.author-info span {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* FAQ Accordion */
.faq-section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border-color);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-question {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  letter-spacing: -0.01em;
}

.faq-icon {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 250ms ease, padding 250ms ease;
  padding: 0 24px;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.faq-item.open .faq-answer {
  max-height: 300px;
  padding-bottom: 20px;
}

/* Footer (Strictly 4 link columns only) */
.site-footer {
  background-color: #FAFAFA;
  border-top: 1px solid var(--border-color);
  padding: 56px 0 36px;
  margin-top: auto;
}

.footer-columns-strict {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border-color);
}

.footer-col h4 {
  font-size: 1rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-col-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 16px;
}

.footer-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  color: var(--accent-color);
  font-weight: 500;
  transition: gap var(--transition-fast);
}

.footer-link-btn:hover {
  gap: 10px;
  color: var(--accent-hover);
}

.footer-bottom {
  padding-top: 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Responsive Media Queries */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .features-grid,
  .pricing-grid,
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .unlock-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-columns-strict {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background-color: #FAFAFA;
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 20px 24px;
    gap: 16px;
  }
  .nav-links.open {
    display: flex;
  }
  .mobile-toggle {
    display: block;
  }
  .trust-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }
  .unlock-grid {
    grid-template-columns: 1fr;
  }
  .footer-columns-strict {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .hero-cta-group {
    flex-direction: column;
    align-items: stretch;
  }
  .hero-cta-group .btn {
    width: 100%;
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}