:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --accent: #06b6d4;
  --accent-gradient: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  --bg-main: #ffffff;
  --bg-alt: #f8fafc;
  --bg-card: #ffffff;
  --border-color: #e2e8f0;
  --border-focus: #3b82f6;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --max-width: 1200px;
  --header-height: 72px;
}

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

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text-main);
  background-color: var(--bg-main);
  line-height: 1.6;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Accessibility: Skip link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 1rem;
  background: var(--primary);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 1rem;
  outline: 3px solid var(--accent);
}

/* Focus outline for keyboard navigation */
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 3px solid var(--border-focus);
  outline-offset: 2px;
}

/* Typography & Layout */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

h1, h2, h3, h4 {
  color: var(--text-main);
  line-height: 1.3;
  font-weight: 700;
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

p {
  color: var(--text-muted);
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s ease;
}
a:hover {
  color: var(--primary-hover);
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  text-decoration: none;
}
.brand-logo .brand-icon {
  width: 32px;
  height: 32px;
  fill: var(--primary);
}
.brand-logo span {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.8rem;
}

.site-nav a {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-main);
  padding: 0.5rem 0.2rem;
  position: relative;
}
.site-nav a:hover {
  color: var(--primary);
}

.nav-cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.5rem 1.25rem;
  background: var(--accent-gradient);
  color: #ffffff !important;
  font-weight: 600;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.nav-cta-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* Hero Section (电影级写实 3D 高空城市飞行动画) */
.hero-section {
  position: relative;
  padding: 6.5rem 0 5.5rem;
  background: #b5d3ec;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  overflow: hidden;
  min-height: 640px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 动效背景总画板 */
.hero-bg-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
  overflow: hidden;
  background: linear-gradient(180deg, #a7cbef 0%, #cce1f5 40%, #e2ecf7 100%);
}

/* 中央轻微渐变遮罩 (确保前景文字纯净清晰，两侧通透展现场景) */
.hero-center-vignette {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 2;
  pointer-events: none;
  background: radial-gradient(ellipse at 50% 50%, rgba(255, 255, 255, 0.45) 0%, rgba(255, 255, 255, 0.15) 55%, rgba(181, 211, 236, 0.4) 100%);
}

/* 前景内容容器及高对比度样式保障 (文字位于最上层，清晰可读) */
.hero-content {
  position: relative;
  z-index: 10;
  max-width: 860px;
  margin: 0 auto;
  padding: 2.25rem 2rem;
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid rgba(255, 255, 255, 0.95);
  box-shadow: 0 20px 45px -12px rgba(15, 23, 42, 0.15), 0 0 0 1px rgba(255, 255, 255, 0.6);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 1.15rem;
  background-color: #dbeafe;
  border: 1px solid #bfdbfe;
  color: #1e40af;
  font-size: 0.875rem;
  font-weight: 700;
  border-radius: 9999px;
  margin-bottom: 1.25rem;
}

.hero-title {
  font-size: 2.75rem;
  margin-bottom: 1.15rem;
  letter-spacing: -0.02em;
  color: #0f172a;
}

.hero-subtitle {
  font-size: 1.3rem;
  color: #2563eb;
  font-weight: 700;
  margin-bottom: 1.25rem;
}

.hero-intro {
  max-width: 760px;
  margin: 0 auto 2.25rem;
  font-size: 1.1rem;
  line-height: 1.8;
  color: #334155;
}

/* Hero CTA 按钮组 (加大尺寸、醒目边框、左右分列布局) */
.hero-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 620px;
  width: 100%;
  margin: 0 auto;
  gap: 1.75rem;
}

.cta-primary {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 58px;
  min-width: 220px;
  padding: 0.95rem 2rem;
  background: var(--accent-gradient);
  color: #ffffff !important;
  font-size: 1.2rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  border: 2px solid #1d4ed8;
  box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.35);
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  letter-spacing: 0.02em;
}
.cta-primary:hover {
  transform: translateY(-2px);
  background: linear-gradient(135deg, #1d4ed8 0%, #0891b2 100%);
  border-color: #1e40af;
  box-shadow: 0 8px 24px 0 rgba(37, 99, 235, 0.45);
}

.cta-secondary {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 58px;
  min-width: 220px;
  padding: 0.95rem 2rem;
  background: #ffffff;
  color: #1d4ed8 !important;
  border: 2px solid #2563eb;
  font-size: 1.2rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 14px 0 rgba(15, 23, 42, 0.08), inset 0 1px 0 rgba(255, 255, 255, 0.9);
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  letter-spacing: 0.02em;
}
.cta-secondary:hover {
  background: #eff6ff;
  border-color: #1d4ed8;
  color: #1e40af !important;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px 0 rgba(37, 99, 235, 0.2);
}

.hero-guarantee {
  margin-top: 1.5rem;
  font-size: 0.9rem;
  color: #475569;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}
.hero-guarantee span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(255, 255, 255, 0.85);
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(226, 232, 240, 0.8);
  font-weight: 500;
}

/* Sections Common */
.section {
  padding: 5rem 0;
}
.section-alt {
  background-color: var(--bg-alt);
}
.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 3.5rem;
}
.section-tag {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.05em;
}
.section-title {
  font-size: 2.15rem;
  margin-bottom: 0.85rem;
}
.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
}

/* Features Cards */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.25rem 1.75rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.card-icon-box {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: #eff6ff;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  color: var(--primary);
}
.card-icon-box svg {
  width: 30px;
  height: 30px;
  fill: currentColor;
}

.feature-card h3 {
  font-size: 1.35rem;
  margin-bottom: 0.85rem;
}
.feature-card p {
  font-size: 0.975rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* Streaming & AI Support Section */
.media-ai-card {
  background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
  color: #f8fafc;
  border-radius: var(--radius-lg);
  padding: 3rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  box-shadow: var(--shadow-lg);
}
.media-ai-card h3 {
  color: #ffffff;
  font-size: 1.85rem;
  margin-bottom: 1rem;
}
.media-ai-card p {
  color: #94a3b8;
  font-size: 1.05rem;
  margin-bottom: 1.5rem;
}
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-bottom: 1.75rem;
}
.tag-item {
  background: rgba(255, 255, 255, 0.1);
  color: #e2e8f0;
  padding: 0.4rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid rgba(255, 255, 255, 0.15);
}
.media-metrics-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
.metric-box {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}
.metric-number {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 0.25rem;
}
.metric-label {
  font-size: 0.85rem;
  color: #cbd5e1;
}

/* Pricing Table Section */
.pricing-table-container {
  width: 100%;
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  background: #ffffff;
  box-shadow: var(--shadow-md);
  margin-bottom: 2rem;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 680px;
}

.pricing-table caption {
  caption-side: top;
  text-align: left;
  padding: 1.25rem 1.5rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  background: #f8fafc;
  border-bottom: 1px solid var(--border-color);
}

.pricing-table th, .pricing-table td {
  padding: 1.2rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.pricing-table th {
  background-color: #f1f5f9;
  font-weight: 700;
  color: var(--text-main);
  font-size: 0.95rem;
}

.pricing-table tbody tr:hover {
  background-color: #f8fafc;
}

.pricing-table tbody tr.featured-tier {
  background-color: #f0fdf4;
}

.price-cell {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--primary);
}
.price-unit {
  font-size: 0.85rem;
  color: var(--text-light);
  font-weight: normal;
}

.badge-popular {
  display: inline-block;
  background-color: #16a34a;
  color: #ffffff;
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: 9999px;
  font-weight: 700;
  margin-left: 0.5rem;
}

.btn-table-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.45rem 1.25rem;
  background-color: var(--primary);
  color: #ffffff !important;
  border-radius: var(--radius-sm);
  font-size: 0.925rem;
  font-weight: 600;
  transition: background-color 0.2s ease;
}
.btn-table-cta:hover {
  background-color: var(--primary-hover);
}

/* User Reviews Section */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.85rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: #f59e0b;
  font-size: 1.15rem;
  margin-bottom: 0.75rem;
}

.review-content {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 1.25rem;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: #e2e8f0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--primary);
}

.author-info h4 {
  font-size: 0.95rem;
  margin-bottom: 0.15rem;
}
.author-info p {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* FAQ Section (Accessible details/summary, default open) */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.2s ease;
}
.faq-item[open] {
  border-color: #93c5fd;
}

.faq-question {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.faq-question::-webkit-details-marker {
  display: none;
}
.faq-question::after {
  content: "▾";
  font-size: 1.25rem;
  color: var(--primary);
  transition: transform 0.2s ease;
}
.faq-item[open] .faq-question::after {
  transform: rotate(180deg);
}

.faq-answer {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--border-color);
  font-size: 0.975rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* Footer (Only 4 links opening in new tab) */
.site-footer {
  margin-top: auto;
  background-color: #0f172a;
  color: #94a3b8;
  padding: 3rem 0 2rem;
  border-top: 1px solid #1e293b;
}

.footer-nav-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 1.75rem;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  color: #e2e8f0;
  font-size: 1.05rem;
  font-weight: 600;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 0 0.5rem;
}
.footer-links a:hover {
  color: var(--accent);
}

.footer-copyright {
  font-size: 0.875rem;
  color: #64748b;
}

/* Article & Content Page Styles */
.article-header {
  padding: 3.5rem 0 2.5rem;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border-color);
}
.article-breadcrumbs {
  font-size: 0.9rem;
  margin-bottom: 1rem;
  color: var(--text-light);
}
.article-breadcrumbs a {
  color: var(--text-muted);
}
.article-breadcrumbs a:hover {
  color: var(--primary);
}
.article-meta {
  display: flex;
  gap: 1.5rem;
  font-size: 0.875rem;
  color: var(--text-light);
  margin-top: 1rem;
}
.article-container {
  max-width: 820px;
  margin: 3rem auto;
  padding: 0 1.5rem;
}
.article-content {
  font-size: 1.05rem;
  line-height: 1.85;
  color: #334155;
}
.article-content h2 {
  font-size: 1.65rem;
  margin: 2.25rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}
.article-content h3 {
  font-size: 1.3rem;
  margin: 1.75rem 0 0.75rem;
}
.article-content p {
  margin-bottom: 1.25rem;
}
.article-content ul, .article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.75rem;
}
.article-content li {
  margin-bottom: 0.5rem;
}
.article-cta-box {
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  border-radius: var(--radius-md);
  padding: 2rem;
  text-align: center;
  margin: 3rem 0;
}
.article-cta-box h3 {
  margin-top: 0;
  color: #1e3a8a;
}
.article-cta-box p {
  color: #1e40af;
  margin-bottom: 1.25rem;
}

/* Knowledge Directory Cards */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin: 3rem 0;
}
.knowledge-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.knowledge-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.knowledge-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}
.knowledge-card h3 a {
  color: var(--text-main);
}
.knowledge-card h3 a:hover {
  color: var(--primary);
}
.knowledge-card p {
  font-size: 0.925rem;
  line-height: 1.6;
  margin-bottom: 1.25rem;
}
.knowledge-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--text-light);
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .features-grid, .reviews-grid, .knowledge-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .media-ai-card {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  .site-header .container {
    padding-left: 1rem;
    padding-right: 1rem;
  }
  .site-nav {
    gap: 0.75rem;
  }
  .site-nav a {
    font-size: 0.9rem;
    padding: 0.4rem;
  }
  .hero-section {
    padding: 3.5rem 0 3rem;
  }
  .hero-title {
    font-size: 2rem;
  }
  .hero-subtitle {
    font-size: 1.15rem;
  }
  .hero-intro {
    font-size: 1rem;
  }
  .hero-actions {
    flex-direction: column;
    width: 100%;
    gap: 1rem;
  }
  .cta-primary, .cta-secondary {
    width: 100%;
    min-height: 54px;
    font-size: 1.15rem;
  }
  .features-grid, .reviews-grid, .knowledge-grid {
    grid-template-columns: 1fr;
  }
  .footer-links {
    flex-direction: column;
    gap: 1rem;
  }
  .footer-links a {
    min-height: 44px;
    padding: 0.5rem 1rem;
  }
  .pricing-table th, .pricing-table td {
    padding: 0.85rem 1rem;
  }
}

@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;
  }
}