/* ==========================================================================
   贝贝云机场 - 浅色雪山主题 (Light Snow Mountain Theme) CSS Style
   ========================================================================== */

:root {
  --bg-main: #f0f7ff;
  --bg-gradient: linear-gradient(135deg, #f0f7ff 0%, #e0f2fe 40%, #eef6ff 70%, #f8fafc 100%);
  --surface-card: rgba(255, 255, 255, 0.75);
  --surface-card-hover: rgba(255, 255, 255, 0.9);
  --surface-border: rgba(255, 255, 255, 0.85);
  --surface-border-accent: rgba(2, 132, 199, 0.25);
  
  --primary: #0284c7;
  --primary-hover: #0369a1;
  --primary-light: #e0f2fe;
  --primary-gradient: linear-gradient(135deg, #0284c7 0%, #2563eb 100%);
  --accent-cyan: #06b6d4;
  --accent-emerald: #10b981;
  
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  
  --shadow-sm: 0 4px 12px rgba(2, 132, 199, 0.06);
  --shadow-md: 0 10px 30px -5px rgba(2, 132, 199, 0.12);
  --shadow-lg: 0 20px 40px -10px rgba(2, 132, 199, 0.2);
  
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-sans);
  background: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
}

/* Dynamic Background Canvas */
#snow-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
}

.page-wrapper {
  position: relative;
  z-index: 1;
  background: var(--bg-gradient);
}

/* Layout Utilities */
.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 90px 0;
  position: relative;
}

/* Typography Elements */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.25;
}

.section-header {
  text-align: center;
  max-width: 750px;
  margin: 0 auto 60px auto;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(2, 132, 199, 0.1);
  border: 1px solid rgba(2, 132, 199, 0.2);
  color: var(--primary);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.section-title {
  font-size: 2.5rem;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #0f172a 0%, #0369a1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 32px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: var(--transition-normal);
  cursor: pointer;
  border: none;
  outline: none;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #ffffff;
  box-shadow: 0 8px 24px -4px rgba(2, 132, 199, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px -4px rgba(2, 132, 199, 0.5);
  color: #ffffff;
}

.btn-secondary {
  background: var(--surface-card);
  color: var(--text-main);
  border: 1px solid var(--surface-border);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
}

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

.btn-glow {
  position: relative;
  overflow: hidden;
}

.btn-glow::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(60deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transform: rotate(30deg);
  animation: shine 4s infinite;
}

@keyframes shine {
  0% { transform: translateX(-100%) rotate(30deg); }
  20%, 100% { transform: translateX(100%) rotate(30deg); }
}

/* Glassmorphism Cards */
.glass-card {
  background: var(--surface-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  transition: var(--transition-normal);
}

.glass-card:hover {
  background: var(--surface-card-hover);
  box-shadow: var(--shadow-lg);
  border-color: var(--surface-border-accent);
}

/* Header & Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 18px 0;
  transition: var(--transition-normal);
}

.navbar.scrolled {
  padding: 12px 0;
  background: rgba(240, 247, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.6);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-main);
  font-weight: 800;
  font-size: 1.35rem;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--primary-gradient);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 6px 16px rgba(2, 132, 199, 0.3);
}

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

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition-fast);
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: var(--transition-fast);
  border-radius: 2px;
}

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

.nav-cta {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* Mobile Nav Toggle */
.mobile-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-main);
  cursor: pointer;
}

/* Hero Section */
.hero {
  padding-top: 170px;
  padding-bottom: 100px;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid rgba(2, 132, 199, 0.2);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.hero-tag-dot {
  width: 8px;
  height: 8px;
  background: var(--accent-emerald);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-emerald);
}

.hero-title {
  font-size: 3.5rem;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.hero-title span {
  background: linear-gradient(135deg, #0284c7 0%, #2563eb 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.2rem;
  color: var(--text-muted);
  margin-bottom: 36px;
  line-height: 1.7;
}

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

.hero-stats {
  display: flex;
  align-items: center;
  gap: 32px;
  padding-top: 24px;
  border-top: 1px solid rgba(2, 132, 199, 0.15);
}

.stat-item h4 {
  font-size: 1.75rem;
  color: var(--primary);
  font-weight: 800;
}

.stat-item p {
  font-size: 0.875rem;
  color: var(--text-light);
}

/* Hero Visual / Mountain Glass Card */
.hero-visual {
  position: relative;
}

.hero-main-card {
  padding: 32px;
  position: relative;
  overflow: hidden;
}

.hero-card-badge {
  position: absolute;
  top: 20px;
  right: 20px;
  padding: 4px 12px;
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
}

.hero-speed-meter {
  text-align: center;
  padding: 30px 0;
}

.meter-circle {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(224, 242, 254, 0.6) 0%, rgba(2, 132, 199, 0.1) 100%);
  border: 3px solid var(--primary-light);
  margin: 0 auto 20px auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 30px rgba(2, 132, 199, 0.2);
}

.meter-num {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--primary);
}

.meter-unit {
  font-size: 0.8rem;
  color: var(--text-light);
  text-transform: uppercase;
}

/* Node Monitor Section */
.node-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.node-card {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.node-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-flag-title {
  display: flex;
  align-items: center;
  gap: 12px;
}

.node-flag {
  font-size: 1.5rem;
}

.node-name {
  font-size: 1.1rem;
  font-weight: 700;
}

.node-type {
  font-size: 0.75rem;
  padding: 3px 8px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.node-metrics {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px;
  background: rgba(240, 247, 255, 0.6);
  border-radius: var(--radius-sm);
}

.metric-ping {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 700;
  color: var(--accent-emerald);
}

.ping-bar {
  display: inline-flex;
  align-items: flex-end;
  gap: 2px;
  height: 14px;
}

.ping-bar span {
  width: 3px;
  background: var(--accent-emerald);
  border-radius: 2px;
}

.ping-bar span:nth-child(1) { height: 6px; }
.ping-bar span:nth-child(2) { height: 10px; }
.ping-bar span:nth-child(3) { height: 14px; }

.node-protocols {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.proto-tag {
  font-size: 0.75rem;
  padding: 2px 8px;
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid rgba(0, 0, 0, 0.06);
  border-radius: 4px;
  color: var(--text-muted);
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-card {
  padding: 36px 28px;
  text-align: left;
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 24px;
}

.feature-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

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

/* Pricing Section */
.pricing-toggle-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 48px;
}

.toggle-label {
  font-weight: 600;
  color: var(--text-muted);
}

.toggle-switch {
  position: relative;
  width: 56px;
  height: 28px;
  background: #cbd5e1;
  border-radius: 14px;
  cursor: pointer;
  transition: var(--transition-fast);
}

.toggle-switch.active {
  background: var(--primary);
}

.toggle-handle {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 22px;
  height: 22px;
  background: #ffffff;
  border-radius: 50%;
  transition: var(--transition-fast);
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.toggle-switch.active .toggle-handle {
  left: 31px;
}

.discount-badge {
  padding: 4px 10px;
  background: #fef3c7;
  color: #d97706;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: var(--radius-full);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  align-items: stretch;
}

.pricing-card {
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.popular {
  border: 2px solid var(--primary);
  transform: translateY(-10px);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-gradient);
  color: #ffffff;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.pricing-name {
  font-size: 1.4rem;
  margin-bottom: 8px;
}

.pricing-desc {
  font-size: 0.875rem;
  color: var(--text-light);
  margin-bottom: 24px;
}

.pricing-price {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 24px;
}

.pricing-currency {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary);
}

.pricing-price-num {
  font-size: 3.6rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1;
  letter-spacing: -0.03em;
}

.pricing-cycle {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-light);
  margin-left: 4px;
}

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

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.pricing-features li svg {
  color: var(--accent-emerald);
  flex-shrink: 0;
}

/* Reviews / Testimonials */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.review-card {
  padding: 28px;
}

.review-rating {
  color: #f59e0b;
  margin-bottom: 16px;
  font-size: 1.1rem;
}

.review-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.6;
}

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

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

.author-info h5 {
  font-size: 0.95rem;
  margin-bottom: 2px;
}

.author-info p {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* FAQ Accordion */
.faq-wrap {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.1rem;
  font-weight: 600;
}

.faq-icon {
  transition: var(--transition-fast);
  color: var(--primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.faq-item.active .faq-answer {
  margin-top: 14px;
  max-height: 250px;
}

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

/* Tutorials / Knowledge Base Grid */
.tutorials-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.tutorial-card {
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 16px;
}

.tutorial-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-light);
}

.tutorial-tag {
  padding: 2px 10px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: var(--radius-full);
  font-weight: 600;
}

.tutorial-card h3 {
  font-size: 1.15rem;
  line-height: 1.4;
}

.tutorial-card h3 a {
  color: var(--text-main);
  text-decoration: none;
  transition: var(--transition-fast);
}

.tutorial-card h3 a:hover {
  color: var(--primary);
}

.tutorial-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.tutorial-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--primary);
  text-decoration: none;
}

.tutorial-link:hover {
  text-decoration: underline;
}

/* Footer */
.footer {
  background: rgba(240, 247, 255, 0.95);
  border-top: 1px solid var(--surface-border);
  padding: 70px 0 30px 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand p {
  color: var(--text-muted);
  margin-top: 16px;
  font-size: 0.95rem;
  max-width: 320px;
}

.footer-col h4 {
  font-size: 1.05rem;
  margin-bottom: 20px;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: var(--transition-fast);
}

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

.footer-bottom {
  padding-top: 30px;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--text-light);
}

/* Article Detail Page Layout (for tutorials/*.html) */
.article-header {
  padding-top: 140px;
  padding-bottom: 40px;
  background: var(--bg-gradient);
  border-bottom: 1px solid var(--surface-border);
}

.article-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-light);
  margin-bottom: 20px;
}

.article-breadcrumb a {
  color: var(--primary);
  text-decoration: none;
}

.article-title {
  font-size: 2.5rem;
  margin-bottom: 16px;
  line-height: 1.2;
}

.article-body {
  padding: 60px 0;
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.8;
  color: #1e293b;
}

.article-body h2 {
  font-size: 1.75rem;
  margin: 40px 0 20px 0;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary-light);
}

.article-body h3 {
  font-size: 1.35rem;
  margin: 28px 0 14px 0;
}

.article-body p {
  margin-bottom: 20px;
}

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

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

.article-body blockquote {
  padding: 16px 24px;
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 24px;
  font-style: italic;
  color: var(--text-main);
}

.article-cta-box {
  margin: 40px 0;
  padding: 32px;
  background: linear-gradient(135deg, #e0f2fe 0%, #ffffff 100%);
  border: 1px solid var(--primary-light);
  border-radius: var(--radius-lg);
  text-align: center;
  box-shadow: var(--shadow-md);
}

.article-cta-box h3 {
  margin-top: 0;
  color: var(--primary);
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .features-grid, .pricing-grid, .reviews-grid { grid-template-columns: 1fr 1fr; }
  .tutorials-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .nav-menu { display: none; }
  .mobile-toggle { display: block; }
  .hero-title { font-size: 2.4rem; }
  .features-grid, .pricing-grid, .reviews-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 14px; text-align: center; }
  .pricing-card.popular { transform: none; }
}