/* ==========================================================================
   网际快车 (NetExpress) - 极简工业风 Design System
   ========================================================================== */

:root {
  /* Color Palette - Industrial Dark & Express Amber/Cyan */
  --bg-primary: #0a0c10;
  --bg-secondary: #11151e;
  --bg-tertiary: #181f2c;
  --bg-card: rgba(22, 28, 40, 0.75);
  --bg-card-hover: rgba(30, 39, 56, 0.9);
  
  --border-color: #242e42;
  --border-color-glow: rgba(0, 229, 255, 0.4);
  --border-accent: #ff5500;

  --text-main: #f0f4f8;
  --text-muted: #8c9baed0;
  --text-dim: #5c6b7e;
  
  --accent-orange: #ff5500;
  --accent-orange-hover: #ff7722;
  --accent-cyan: #00e5ff;
  --accent-cyan-hover: #33ebff;
  --accent-green: #10b981;

  --font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 20px;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(255, 85, 0, 0.25);
  
  --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 & Base Styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(255, 85, 0, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 60%, rgba(0, 229, 255, 0.04) 0%, transparent 40%),
    linear-gradient(to bottom, rgba(10, 12, 16, 0.95), rgba(10, 12, 16, 0.98));
}

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

a:hover {
  color: var(--accent-cyan-hover);
}

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

/* Typography & Title Style */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.brand-title {
  font-family: var(--font-family);
  font-weight: 900;
  background: linear-gradient(135deg, #ffffff 0%, #d0d7de 50%, var(--accent-orange) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.03em;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.825rem;
  color: var(--accent-cyan);
  background: rgba(0, 229, 255, 0.08);
  border: 1px solid rgba(0, 229, 255, 0.2);
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.section-tag::before {
  content: "";
  width: 6px;
  height: 6px;
  background-color: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 6px var(--accent-cyan);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 50px auto;
}

.section-header h2 {
  font-size: 2.25rem;
  margin-bottom: 16px;
}

.section-header p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* Layout Components */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 90px 0;
  position: relative;
  border-bottom: 1px solid rgba(36, 46, 66, 0.4);
}

/* Industrial Header / Navbar */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(10, 12, 16, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
  transition: all var(--transition-normal);
}

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

.logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-main);
  font-size: 1.35rem;
  font-weight: 900;
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-orange), #ff2200);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 12px rgba(255, 85, 0, 0.4);
}

.logo-icon svg {
  width: 22px;
  height: 22px;
  fill: #ffffff;
}

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

.nav-link {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition-fast);
  position: relative;
  padding: 6px 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-main);
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--accent-orange);
  box-shadow: 0 0 8px var(--accent-orange);
}

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

.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-orange) 0%, #ff3a00 100%);
  color: #ffffff;
  box-shadow: 0 4px 16px rgba(255, 85, 0, 0.35);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--accent-orange-hover) 0%, #ff5500 100%);
  color: #ffffff;
  box-shadow: 0 6px 24px rgba(255, 85, 0, 0.5);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background: rgba(36, 46, 66, 0.8);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--accent-cyan);
  border-color: rgba(0, 229, 255, 0.3);
}

.btn-outline:hover {
  background: rgba(0, 229, 255, 0.1);
  border-color: var(--accent-cyan);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.05rem;
}

/* Hero Section */
.hero-section {
  padding: 100px 0 90px 0;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 50px;
  align-items: center;
}

.hero-content h1 {
  font-size: 3.25rem;
  line-height: 1.15;
  margin-bottom: 24px;
}

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

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

.hero-stats {
  display: flex;
  gap: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

.stat-item .stat-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent-cyan);
}

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

/* Hero Dynamic Tech Cards Showcase */
.hero-cards-wrapper {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.tech-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
  display: flex;
  align-items: center;
  gap: 20px;
}

.tech-card:hover {
  border-color: var(--border-color-glow);
  transform: translateX(6px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

.tech-card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: rgba(0, 229, 255, 0.1);
  border: 1px solid rgba(0, 229, 255, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--accent-cyan);
}

.tech-card-info h4 {
  font-size: 1.05rem;
  margin-bottom: 4px;
}

.tech-card-info p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.status-badge {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-green);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

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

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--accent-orange), transparent);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.feature-card:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 85, 0, 0.3);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  width: 56px;
  height: 56px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  color: var(--accent-orange);
}

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

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

/* Streaming & AI Support Section */
.services-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 40px;
}

.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  transition: all var(--transition-fast);
}

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

.service-icon-wrap {
  width: 50px;
  height: 50px;
  margin: 0 auto 16px auto;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.05);
}

.service-card h4 {
  font-size: 1.05rem;
  margin-bottom: 6px;
}

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

.disclaimer-box {
  background: rgba(36, 46, 66, 0.4);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px 24px;
  text-align: center;
  font-size: 0.875rem;
  color: var(--text-muted);
  max-width: 800px;
  margin: 0 auto;
}

.disclaimer-box span {
  color: var(--accent-cyan);
  font-weight: 600;
}

/* Pricing Section */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-normal);
}

.pricing-card.popular {
  border-color: var(--accent-orange);
  background: linear-gradient(180deg, rgba(255, 85, 0, 0.08) 0%, rgba(22, 28, 40, 0.9) 100%);
  box-shadow: 0 0 30px rgba(255, 85, 0, 0.15);
}

.popular-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-orange);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 14px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-header {
  margin-bottom: 24px;
  text-align: center;
}

.plan-name {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.plan-price {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 4px;
}

.price-currency {
  font-size: 1.25rem;
  color: var(--text-muted);
}

.price-amount {
  font-family: var(--font-mono);
  font-size: 2.75rem;
  font-weight: 900;
  color: var(--text-main);
}

.price-period {
  font-size: 0.875rem;
  color: var(--text-muted);
}

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

.plan-features li {
  padding: 10px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.9rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 10px;
}

.plan-features li::before {
  content: "✓";
  color: var(--accent-cyan);
  font-weight: bold;
}

.pricing-card.popular .plan-features li::before {
  color: var(--accent-orange);
}

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

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

.faq-item.active {
  border-color: var(--accent-cyan);
}

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

.faq-toggle-icon {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast);
  color: var(--accent-cyan);
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
  background: rgba(10, 12, 16, 0.4);
}

.faq-answer-inner {
  padding: 0 24px 20px 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* Right Side Floating Section Navigation Arrows */
.section-nav-arrows {
  position: fixed;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 900;
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: rgba(17, 21, 30, 0.85);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  padding: 10px 8px;
  border-radius: 30px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
}

.nav-arrow-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.nav-arrow-btn:hover:not(:disabled) {
  background: var(--accent-orange);
  border-color: var(--accent-orange);
  color: #ffffff;
  box-shadow: 0 0 12px rgba(255, 85, 0, 0.5);
}

.nav-arrow-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
  border-color: transparent;
}

/* Footer Section - Strict 4 links requirement */
.site-footer {
  background: #07090d;
  border-top: 1px solid var(--border-color);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  color: var(--text-main);
}

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

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

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

.footer-copy {
  color: var(--text-dim);
  font-size: 0.85rem;
  width: 100%;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  text-align: center;
}

/* Articles Layout (Knowledge Column) */
.article-page {
  padding: 60px 0;
}

.article-header {
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.article-header h1 {
  font-size: 2.25rem;
  margin-bottom: 16px;
  line-height: 1.3;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  color: var(--text-muted);
  font-size: 0.875rem;
  font-family: var(--font-mono);
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #d1d9e6;
  max-width: 860px;
}

.article-content p {
  margin-bottom: 24px;
}

.article-content h2 {
  font-size: 1.6rem;
  margin: 40px 0 20px 0;
  color: var(--text-main);
  border-left: 4px solid var(--accent-orange);
  padding-left: 14px;
}

.article-content h3 {
  font-size: 1.25rem;
  margin: 30px 0 16px 0;
  color: var(--accent-cyan);
}

.article-content ul, .article-content ol {
  margin: 0 0 24px 24px;
}

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

.article-content blockquote {
  background: var(--bg-card);
  border-left: 4px solid var(--accent-cyan);
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--text-muted);
}

.article-promo-box {
  background: linear-gradient(135deg, rgba(255, 85, 0, 0.1) 0%, rgba(0, 229, 255, 0.05) 100%);
  border: 1px solid rgba(255, 85, 0, 0.3);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin: 40px 0;
  text-align: center;
}

.article-promo-box h4 {
  font-size: 1.35rem;
  margin-bottom: 12px;
  color: var(--text-main);
}

.article-promo-box p {
  color: var(--text-muted);
  margin-bottom: 20px;
  font-size: 0.95rem;
}

/* Articles List Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
}

.article-card:hover {
  border-color: var(--accent-cyan);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.article-card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
  line-height: 1.4;
}

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

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .articles-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .site-header {
    padding: 12px 0;
  }

  .mobile-menu-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 65px;
    left: 0;
    width: 100%;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    transform: translateY(-150%);
    transition: transform var(--transition-normal);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.5);
  }

  .nav-menu.active {
    transform: translateY(0);
  }

  .hero-content h1 {
    font-size: 2.25rem;
  }

  .features-grid, .pricing-grid, .services-grid {
    grid-template-columns: 1fr;
  }

  .section-nav-arrows {
    right: 12px;
    padding: 6px 4px;
    gap: 8px;
  }

  .nav-arrow-btn {
    width: 34px;
    height: 34px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
  }
}

/* Reduced Motion Respect */
@media (prefers-reduced-motion: reduce) {
  *, ::before, ::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}