/* ==========================================================================
   OKZTWO 机场 — 02:00 AM Control Tower Design System
   Pure Native CSS · Zero Gradients · Hairline Precision · 12-Column Grid
   ========================================================================== */

:root {
  --bg-tower: #0B1220;
  --bg-panel: #111B2E;
  --border-hairline: rgba(231, 238, 248, 0.16);
  --text-primary: #E7EEF8;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --signal-cyan: #5EEAD4;
  --font-heading: 'Space Grotesk', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--bg-tower);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-tower);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  animation: towerFadeIn 200ms ease forwards;
}

@keyframes towerFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes statusPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.32; }
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 200ms ease, border-color 200ms ease, background-color 200ms ease, opacity 200ms ease;
}

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

/* 12-Column Grid Container */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.col-12 { grid-column: span 12; }
.col-8 { grid-column: span 8; }
.col-6 { grid-column: span 6; }
.col-4 { grid-column: span 4; }
.col-3 { grid-column: span 3; }

/* Typography */
h1, h2, h3, h4, .brand-wordmark {
  font-family: var(--font-heading);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.mono {
  font-family: var(--font-mono);
}

.brand-two {
  color: var(--signal-cyan);
}

/* Live Status Dot */
.status-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--signal-cyan);
  animation: statusPulse 2.4s ease-in-out infinite;
  vertical-align: middle;
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-tower);
  border-bottom: 1px solid var(--border-hairline);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  gap: 24px;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 12px;
}

.brand-logo-img {
  width: 36px;
  height: 36px;
}

.brand-wordmark {
  font-size: 1.25rem;
  letter-spacing: 0.04em;
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.brand-subtag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.92rem;
  color: var(--text-secondary);
  padding: 6px 0;
  border-bottom: 1px solid transparent;
}

.nav-link:hover,
.nav-link.active {
  color: var(--signal-cyan);
  border-bottom-color: var(--signal-cyan);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 12px 24px;
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 4px;
  border: 1px solid var(--border-hairline);
  cursor: pointer;
  transition: color 200ms ease, background-color 200ms ease, border-color 200ms ease, opacity 200ms ease;
  text-align: center;
}

.btn-primary {
  background-color: var(--signal-cyan);
  color: var(--bg-tower);
  border-color: var(--signal-cyan);
}

.btn-primary:hover {
  background-color: var(--bg-panel);
  color: var(--signal-cyan);
  border-color: var(--signal-cyan);
}

.btn-outline {
  background-color: var(--bg-panel);
  color: var(--text-primary);
  border-color: var(--border-hairline);
}

.btn-outline:hover {
  color: var(--signal-cyan);
  border-color: var(--signal-cyan);
}

.btn-sm {
  min-height: 40px;
  padding: 8px 18px;
  font-size: 0.875rem;
}

/* Section Layout & Generous Whitespace */
.section {
  padding: 96px 0;
  border-bottom: 1px solid var(--border-hairline);
}

.section-header {
  margin-bottom: 56px;
}

.section-kicker {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--signal-cyan);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-title {
  font-size: 2.15rem;
  line-height: 1.25;
  margin-bottom: 14px;
}

.section-desc {
  color: var(--text-secondary);
  max-width: 680px;
  font-size: 1.02rem;
}

/* Hero Section */
.hero-section {
  padding: 112px 0 88px;
  border-bottom: 1px solid var(--border-hairline);
}

.hero-telemetry-bar {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 6px 14px;
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
}

.hero-headline {
  font-size: clamp(2.6rem, 5.6vw, 4.75rem);
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.hero-headline .headline-brand {
  display: block;
  font-size: clamp(1.35rem, 2.4vw, 2rem);
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 10px;
  letter-spacing: 0.02em;
}

.hero-subtitle {
  font-size: 1.3rem;
  color: var(--text-primary);
  font-weight: 500;
  margin-bottom: 16px;
  max-width: 780px;
}

.hero-intro {
  font-size: 1.02rem;
  color: var(--text-secondary);
  max-width: 740px;
  margin-bottom: 40px;
  line-height: 1.75;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 64px;
}

/* Live Departure Board */
.departure-board {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  overflow: hidden;
}

.board-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border-hairline);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.board-title {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
}

.board-table-wrap {
  width: 100%;
  overflow-x: auto;
}

.board-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-align: left;
}

.board-table th,
.board-table td {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border-hairline);
  white-space: nowrap;
}

.board-table th {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.board-table tbody tr {
  transition: background-color 200ms ease;
}

.board-table tbody tr:last-child td {
  border-bottom: none;
}

.board-table tbody tr:hover {
  background-color: rgba(231, 238, 248, 0.03);
}

.flight-code {
  color: var(--signal-cyan);
  font-weight: 600;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--signal-cyan);
  font-size: 0.8rem;
}

/* Panels & Cards */
.panel-card {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  padding: 28px;
  transition: border-color 200ms ease;
  display: flex;
  flex-direction: column;
  height: 100%;
}

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

.card-media {
  margin-bottom: 22px;
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  overflow: hidden;
  background-color: var(--bg-tower);
}

.card-code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--signal-cyan);
  margin-bottom: 8px;
}

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

.card-text {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 20px;
  flex-grow: 1;
}

.card-meta-list {
  list-style: none;
  border-top: 1px solid var(--border-hairline);
  padding-top: 16px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.card-meta-list li {
  display: flex;
  justify-content: space-between;
}

.card-meta-list span:last-child {
  color: var(--text-primary);
}

/* Streaming & AI Support Matrix */
.matrix-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.matrix-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 6px 12px;
  background-color: var(--bg-tower);
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

/* Pricing Cards & Comparison Table */
.pricing-card {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: border-color 200ms ease;
}

.pricing-card:hover,
.pricing-card.featured {
  border-color: var(--signal-cyan);
}

.plan-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--signal-cyan);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.plan-name {
  font-size: 1.35rem;
  margin-bottom: 16px;
}

.plan-price {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.plan-price small {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--text-secondary);
}

.plan-cycles {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  padding-bottom: 18px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--border-hairline);
}

.plan-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 28px;
  flex-grow: 1;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.plan-features li {
  display: flex;
  justify-content: space-between;
}

.plan-features strong {
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-weight: 500;
}

.comparison-panel {
  margin-top: 40px;
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  overflow: hidden;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-hairline);
}

.comparison-table th {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.comparison-table tbody tr:last-child td {
  border-bottom: none;
}

.comparison-table tbody tr:hover {
  background-color: rgba(231, 238, 248, 0.03);
}

/* User Reviews */
.review-quote {
  color: var(--text-primary);
  font-size: 0.96rem;
  line-height: 1.75;
  margin-bottom: 22px;
  flex-grow: 1;
}

.review-footer {
  border-top: 1px solid var(--border-hairline);
  padding-top: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.review-score {
  color: var(--signal-cyan);
}

/* FAQ Accordion / Grid */
.faq-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.faq-item {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  padding: 26px;
  transition: border-color 200ms ease;
}

.faq-item:hover {
  border-color: var(--signal-cyan);
}

.faq-q {
  font-size: 1.08rem;
  margin-bottom: 10px;
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.faq-q-code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--signal-cyan);
  flex-shrink: 0;
}

.faq-a {
  color: var(--text-secondary);
  font-size: 0.94rem;
  line-height: 1.7;
}

/* Footer (Strictly 4 Titles Opening New Pages) */
.site-footer {
  padding: 56px 0;
  background-color: var(--bg-tower);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 24px;
}

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

.footer-links a {
  font-size: 0.95rem;
  color: var(--text-secondary);
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}

.footer-links a:hover {
  color: var(--signal-cyan);
  border-bottom-color: var(--signal-cyan);
}

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

/* Subpages & SEO Articles Layout */
.article-card {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-hairline);
  border-radius: 6px;
  padding: 36px;
  margin-bottom: 32px;
  transition: border-color 200ms ease;
}

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

.article-meta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--signal-cyan);
  margin-bottom: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.article-card h2 {
  font-size: 1.5rem;
  margin-bottom: 16px;
  line-height: 1.35;
}

.article-card h3 {
  font-size: 1.12rem;
  margin: 22px 0 10px;
  color: var(--text-primary);
}

.article-card p {
  color: var(--text-secondary);
  margin-bottom: 14px;
  line-height: 1.8;
}

.article-card ul {
  margin: 12px 0 18px 20px;
  color: var(--text-secondary);
}

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

.article-card a.seo-link {
  color: var(--signal-cyan);
  border-bottom: 1px solid var(--signal-cyan);
  padding-bottom: 1px;
}

.article-card a.seo-link:hover {
  opacity: 0.8;
}

/* Responsive Media Queries (@media) */
@media (max-width: 992px) {
  .col-8, .col-6, .col-4, .col-3 {
    grid-column: span 6;
  }
  .faq-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 64px 0;
  }
  .hero-section {
    padding: 72px 0 56px;
  }
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    padding: 16px 0;
    gap: 14px;
  }
  .main-nav {
    width: 100%;
    flex-wrap: wrap;
    gap: 14px 20px;
  }
  .header-actions {
    width: 100%;
  }
  .header-actions .btn {
    width: 100%;
  }
  .grid-12 {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .col-12, .col-8, .col-6, .col-4, .col-3 {
    grid-column: span 1;
  }
  .hero-cta-group {
    flex-direction: column;
  }
  .hero-cta-group .btn {
    width: 100%;
    min-height: 52px;
  }
  .pricing-card .btn {
    width: 100%;
    min-height: 50px;
  }
  .article-card {
    padding: 24px;
  }
  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-links {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
}