/* ==========================================================================
   一云梯机场 (Yiyunti Airport) - Kinetic Ascent & Webbing Strap Theme
   Substrate: Industrial Concrete Dark Slate (#0c0e11, #13161c)
   Accent: Fluorescent Glacier Cyan (#00f0ff) & Safety Amber (#ff5500)
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700;800;900&family=JetBrains+Mono:wght@400;700;800&family=Noto+Sans+SC:wght@400;500;700;900&display=swap');

:root {
  --bg-slate-dark: #0c0e11;
  --bg-slate-card: #13161c;
  --bg-slate-card-hover: #191d25;
  --bg-concrete: #1c2028;
  
  --glacier-cyan: #00f0ff;
  --glacier-cyan-glow: rgba(0, 240, 255, 0.25);
  --glacier-cyan-dark: #0099aa;
  
  --safety-amber: #ff5500;
  --safety-amber-glow: rgba(255, 85, 0, 0.3);
  
  --text-main: #f0f4f8;
  --text-muted: #8c98a9;
  --text-dim: #5c6878;
  
  --border-slate: #252a34;
  --border-cyan: rgba(0, 240, 255, 0.35);
  --border-amber: rgba(255, 85, 0, 0.35);
  
  --font-sans: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  
  --container-max: 1240px;
  --transition-fast: 0.2s cubic-bezier(0.2, 0.8, 0.2, 1);
  --transition-lock: 0.35s cubic-bezier(0.68, -0.6, 0.32, 1.6);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-slate-dark);
  color: var(--text-main);
  font-family: var(--font-sans);
  overflow-x: hidden;
}

body {
  position: relative;
  min-height: 100vh;
  line-height: 1.6;
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(0, 240, 255, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 80%, rgba(255, 85, 0, 0.04) 0%, transparent 45%),
    linear-gradient(to bottom, rgba(12, 14, 17, 0.85), rgba(12, 14, 17, 0.98)),
    repeating-linear-gradient(0deg, transparent, transparent 3px, rgba(255, 255, 255, 0.015) 3px, rgba(255, 255, 255, 0.015) 4px);
  background-attachment: fixed;
}

/* Vertical Staggered Typographic Background Watermark "LADDER / ONE / CLOUD" */
body::before {
  content: "LADDER  ONE  CLOUD  ASCENT";
  position: fixed;
  top: 10%;
  left: -5vw;
  font-family: var(--font-mono);
  font-size: clamp(80px, 14vw, 220px);
  font-weight: 900;
  color: rgba(255, 255, 255, 0.018);
  letter-spacing: -0.05em;
  line-height: 0.85;
  pointer-events: none;
  z-index: 0;
  white-space: nowrap;
  transform: rotate(-90deg);
  transform-origin: top left;
}

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

a:hover {
  color: #fff;
}

/* Kinetic Webbing Strap Accent Utilities */
.webbing-strap {
  position: relative;
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-left: 4px solid var(--glacier-cyan);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

.webbing-strap::before {
  content: "";
  position: absolute;
  top: 0;
  right: 12px;
  width: 24px;
  height: 6px;
  background: repeating-linear-gradient(90deg, var(--glacier-cyan), var(--glacier-cyan) 4px, transparent 4px, transparent 8px);
}

/* Punch Holes Webbing Texture */
.punch-holes {
  background-image: radial-gradient(var(--border-slate) 20%, transparent 20%);
  background-size: 10px 10px;
}

/* Mechanical Carabiner Button */
.btn-ascent {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 32px;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #000;
  background: var(--glacier-cyan);
  border: none;
  border-radius: 4px;
  position: relative;
  cursor: pointer;
  box-shadow: 0 0 20px var(--glacier-cyan-glow);
  transition: transform var(--transition-lock), box-shadow var(--transition-fast), background var(--transition-fast);
  overflow: hidden;
  z-index: 1;
}

.btn-ascent::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 0;
  height: 100%;
  background: rgba(255, 255, 255, 0.3);
  transition: width 0.3s ease;
}

.btn-ascent:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 0 35px rgba(0, 240, 255, 0.6);
  color: #000;
}

.btn-ascent:hover::after {
  width: 100%;
  left: 0;
}

.btn-amber {
  background: var(--safety-amber);
  box-shadow: 0 0 20px var(--safety-amber-glow);
  color: #fff;
}

.btn-amber:hover {
  box-shadow: 0 0 35px rgba(255, 85, 0, 0.6);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--glacier-cyan);
  border: 1px solid var(--border-cyan);
  box-shadow: none;
}

.btn-outline:hover {
  background: rgba(0, 240, 255, 0.1);
  color: #fff;
  border-color: var(--glacier-cyan);
}

/* Altimeter Telemetry Module Tag */
.telemetry-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 10px;
  background: rgba(0, 240, 255, 0.08);
  border: 1px solid var(--border-cyan);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--glacier-cyan);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.telemetry-dot {
  width: 6px;
  height: 6px;
  background: var(--glacier-cyan);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--glacier-cyan);
  animation: pulse-dot 1.8s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

/* Layout Containers */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 2;
}

/* Header & Navbar */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(12, 14, 17, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-slate);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 900;
  color: #fff;
  letter-spacing: -0.02em;
}

.brand-logo svg {
  width: 36px;
  height: 36px;
  fill: none;
  stroke: var(--glacier-cyan);
}

.brand-badge {
  font-size: 0.65rem;
  padding: 2px 6px;
  background: var(--safety-amber);
  color: #fff;
  border-radius: 2px;
  vertical-align: middle;
}

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

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--glacier-cyan);
}

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

/* Mobile Nav Toggle */
.mobile-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-slate);
  color: var(--glacier-cyan);
  padding: 8px 12px;
  border-radius: 4px;
  cursor: pointer;
  font-family: var(--font-mono);
}

/* Hero Section */
.hero-section {
  padding: 90px 0 70px;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 60px;
  align-items: center;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4.2rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.hero-title span.cyan-glow {
  color: var(--glacier-cyan);
  text-shadow: 0 0 25px rgba(0, 240, 255, 0.4);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 36px;
  max-width: 620px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin-bottom: 48px;
}

.hero-stats {
  display: flex;
  gap: 36px;
  padding-top: 32px;
  border-top: 1px solid var(--border-slate);
}

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

.stat-val {
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--glacier-cyan);
}

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

/* Telemetry Altitude Visual Card */
.hero-card {
  position: relative;
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 8px;
  padding: 24px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6);
  overflow: hidden;
}

.hero-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--glacier-cyan), var(--safety-amber));
}

.telemetry-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border-slate);
}

.telemetry-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.node-status-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.node-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

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

.flag-icon {
  font-size: 1.1rem;
}

.node-ping {
  color: #38ef7d;
  font-weight: 700;
}

/* Section Header */
.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto;
}

/* Core Advantages Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
  margin-bottom: 90px;
}

.feature-card {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  padding: 32px 28px;
  border-radius: 6px;
  position: relative;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--glacier-cyan);
}

.feature-icon {
  width: 52px;
  height: 52px;
  background: rgba(0, 240, 255, 0.08);
  border: 1px solid var(--border-cyan);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  color: var(--glacier-cyan);
}

.feature-icon svg {
  width: 28px;
  height: 28px;
  stroke: var(--glacier-cyan);
  fill: none;
  stroke-width: 2;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Pricing Section (Matching Reference Screenshot) */
.pricing-section {
  padding: 80px 0;
  background: rgba(19, 22, 28, 0.6);
  border-y: 1px solid var(--border-slate);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  max-width: 1140px;
  margin: 0 auto;
}

.pricing-card {
  position: relative;
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 12px;
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-lock), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.pricing-card:hover {
  transform: translateY(-8px);
}

.pricing-card.popular {
  border: 2px solid var(--glacier-cyan);
  box-shadow: 0 0 35px rgba(0, 240, 255, 0.25);
  background: linear-gradient(180deg, rgba(0, 240, 255, 0.05) 0%, var(--bg-slate-card) 100%);
}

.plan-badge {
  position: absolute;
  top: 24px;
  right: 24px;
  padding: 4px 12px;
  font-size: 0.75rem;
  font-weight: 800;
  border-radius: 20px;
  font-family: var(--font-mono);
}

.badge-gray {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-muted);
}

.badge-cyan {
  background: var(--glacier-cyan);
  color: #000;
}

.badge-amber {
  background: var(--safety-amber);
  color: #fff;
}

.plan-name {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.plan-price {
  font-family: var(--font-mono);
  font-size: 2.8rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 12px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price span.unit {
  font-size: 1.2rem;
  font-weight: 400;
}

.plan-price span.period {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 400;
}

.plan-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-slate);
}

.plan-features {
  list-style: none;
  margin-bottom: 36px;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.plan-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-main);
}

.check-icon {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: rgba(0, 240, 255, 0.15);
  color: var(--glacier-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 800;
  flex-shrink: 0;
}

/* Tutorials Preview Cards */
.tutorials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.tutorial-card {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 8px;
  padding: 28px;
  transition: border-color var(--transition-fast);
}

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

.client-logo {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--glacier-cyan);
  margin-bottom: 12px;
}

/* User Testimonials */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
}

.testimonial-card {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-left: 3px solid var(--safety-amber);
  padding: 28px;
  border-radius: 4px;
}

.user-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 20px;
}

.avatar-box {
  width: 42px;
  height: 42px;
  background: var(--bg-concrete);
  border: 1px solid var(--border-cyan);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-weight: 800;
  color: var(--glacier-cyan);
}

/* Accordion FAQ Component */
.faq-accordion {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 6px;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-size: 1.05rem;
  font-weight: 700;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-family: var(--font-sans);
}

.faq-toggle {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  color: var(--glacier-cyan);
  transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 24px 20px;
}

/* Articles Directory Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 28px;
}

.article-card {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 8px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--glacier-cyan);
}

.article-body {
  padding: 28px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--glacier-cyan);
  text-transform: uppercase;
  margin-bottom: 12px;
}

.article-title {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 14px;
  color: var(--text-main);
}

.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.6;
  flex-grow: 1;
}

.article-meta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
  display: flex;
  justify-content: space-between;
  border-top: 1px dashed var(--border-slate);
  padding-top: 14px;
}

/* Breadcrumbs */
.breadcrumb-trail {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 32px;
}

.breadcrumb-trail a {
  color: var(--text-muted);
}

.breadcrumb-trail a:hover {
  color: var(--glacier-cyan);
}

/* Article Content Layout */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 48px;
  padding: 60px 0;
}

.article-main {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 8px;
  padding: 48px 40px;
}

.article-main h1 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 24px;
}

.article-main h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin: 36px 0 16px;
  color: var(--glacier-cyan);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-slate);
}

.article-main h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 24px 0 12px;
  color: var(--text-main);
}

.article-main p {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 20px;
}

.article-main ul, .article-main ol {
  margin: 0 0 24px 24px;
  color: var(--text-muted);
  line-height: 1.8;
}

.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.sidebar-widget {
  background: var(--bg-slate-card);
  border: 1px solid var(--border-slate);
  border-radius: 8px;
  padding: 24px;
}

.widget-title {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 800;
  margin-bottom: 16px;
  color: var(--glacier-cyan);
}

/* Footer Section */
.site-footer {
  background: #08090b;
  border-top: 1px solid var(--border-slate);
  padding: 70px 0 30px;
  margin-top: 100px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 60px;
}

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 800;
  color: var(--glacier-cyan);
  margin-bottom: 20px;
  text-transform: uppercase;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--glacier-cyan);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 30px;
  border-top: 1px dashed var(--border-slate);
  font-size: 0.85rem;
  color: var(--text-dim);
}

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

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  .mobile-toggle {
    display: block;
  }
  .hero-actions {
    flex-direction: column;
  }
  .btn-ascent {
    width: 100%;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
}