/* ==========================================================================
   闪电猫 Lightning Cat - Electric Blue Network Design System
   Color Palette:
     Background: #071426
     Panel: #0D2038
     Sub-panel / Card: #112845
     Border: #203D5A
     Border Hover: #38BDF8
     Primary Electric Cyan: #38BDF8
     Primary Cyan Hover: #0284C7
     Accent Electric Yellow: #F5EA61
     Heading: #F3F8FF
     Body / Subtext: #A9BDD2
     Muted / Tertiary: #64748B
   ========================================================================== */

:root {
  --bg-main: #071426;
  --bg-panel: #0D2038;
  --bg-card: #102540;
  --bg-card-hover: #142F50;
  --bg-alt: #0B1C33;
  --border-color: #203D5A;
  --border-glow: rgba(56, 189, 248, 0.4);
  --primary: #38BDF8;
  --primary-hover: #7DD3FC;
  --primary-dark: #0284C7;
  --accent-yellow: #F5EA61;
  --accent-yellow-dark: #EAB308;
  --text-heading: #F3F8FF;
  --text-body: #A9BDD2;
  --text-muted: #64748B;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  --font-main: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --shadow-panel: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.15);
  --shadow-glow-yellow: 0 0 25px rgba(245, 234, 97, 0.2);
  --container-max: 1200px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

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

html {
  font-family: var(--font-main);
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.65;
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  max-width: 100%;
  overflow-x: hidden;
}

body {
  min-height: 100vh;
  max-width: 100%;
  overflow-x: hidden;
  background-color: var(--bg-main);
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(56, 189, 248, 0.08) 0%, transparent 60%),
    radial-gradient(circle at 100% 50%, rgba(14, 40, 74, 0.4) 0%, transparent 50%);
  background-repeat: no-repeat;
}

/* Accessibility: Focus outlines */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}

/* Skip link for keyboard accessibility */
.skip-link {
  position: absolute;
  top: -100px;
  left: 20px;
  background: var(--primary);
  color: #071426;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  z-index: 9999;
  text-decoration: none;
  transition: top var(--transition-fast);
}
.skip-link:focus {
  top: 20px;
}

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

p {
  margin-bottom: 1rem;
}

p:last-child {
  margin-bottom: 0;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

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

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

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 16px;
  padding-right: 16px;
}

@media (min-width: 768px) {
  .container {
    padding-left: 24px;
    padding-right: 24px;
  }
}

/* Section Common Styling */
.section {
  padding: 72px 0;
  position: relative;
}

@media (min-width: 768px) {
  .section {
    padding: 96px 0;
  }
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 48px auto;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 9999px;
  background-color: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.section-badge-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--accent-yellow);
  box-shadow: 0 0 8px var(--accent-yellow);
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

@media (min-width: 768px) {
  .section-title {
    font-size: 2.5rem;
  }
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-body);
  line-height: 1.7;
}

/* Buttons & Commercial CTA */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, #38BDF8 0%, #0284C7 100%);
  color: #071426;
  font-weight: 700;
  box-shadow: 0 4px 16px rgba(56, 189, 248, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #7DD3FC 0%, #0284C7 100%);
  color: #071426;
  box-shadow: 0 6px 24px rgba(56, 189, 248, 0.45);
  transform: translateY(-2px);
}

.btn-outline {
  background: rgba(13, 32, 56, 0.8);
  border-color: var(--border-color);
  color: var(--text-heading);
}

.btn-outline:hover {
  border-color: var(--primary);
  background: rgba(14, 40, 74, 0.8);
  color: var(--primary);
  transform: translateY(-2px);
}

.btn-accent {
  background: linear-gradient(135deg, #F5EA61 0%, #EAB308 100%);
  color: #071426;
  font-weight: 700;
  box-shadow: 0 4px 16px rgba(245, 234, 97, 0.35);
}

.btn-accent:hover {
  background: linear-gradient(135deg, #FEF08A 0%, #CA8A04 100%);
  color: #071426;
  box-shadow: 0 6px 24px rgba(245, 234, 97, 0.5);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 14px 30px;
  font-size: 1.05rem;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
}

/* ==========================================================================
   Header & Sticky Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(7, 20, 38, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-color);
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-heading);
  text-decoration: none;
  min-width: 0;
  flex-shrink: 1;
}

.brand-logo {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.brand-title-wrap {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-name {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text-heading);
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.brand-name span {
  color: var(--primary);
  font-size: 0.76rem;
  font-weight: 600;
  text-transform: uppercase;
}

.brand-sub {
  font-size: 0.68rem;
  color: var(--text-muted);
  letter-spacing: 0.3px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

@media (max-width: 768px) {
  .brand-sub {
    display: none;
  }
  .header-actions .btn {
    display: none !important;
  }
}

.main-nav {
  display: none;
}

@media (min-width: 1024px) {
  .main-nav {
    display: flex;
    align-items: center;
    gap: 20px;
  }
}

.nav-link {
  color: var(--text-body);
  font-size: 0.92rem;
  font-weight: 500;
  padding: 6px 4px;
  position: relative;
  transition: color var(--transition-fast);
}

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background-color: var(--primary);
  transition: width var(--transition-fast);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

@media (max-width: 768px) {
  .brand-sub {
    display: none;
  }
  .header-actions .btn {
    display: none !important;
  }
}

@media (max-width: 480px) {
  .brand-name span {
    display: none;
  }
}

.menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  color: var(--text-heading);
  cursor: pointer;
  transition: all var(--transition-fast);
}

@media (min-width: 1024px) {
  .menu-toggle {
    display: none;
  }
}

.menu-toggle:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.menu-icon {
  width: 22px;
  height: 22px;
  fill: currentColor;
}

/* Mobile Drawer */
.mobile-nav-drawer {
  position: fixed;
  top: 72px;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(7, 20, 38, 0.98);
  border-top: 1px solid var(--border-color);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  overflow-y: auto;
  transform: translateY(-110%);
  transition: transform var(--transition-normal);
  z-index: 999;
}

.mobile-nav-drawer.open {
  transform: translateY(0);
}

.mobile-nav-link {
  color: var(--text-heading);
  font-size: 1.15rem;
  font-weight: 600;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

.mobile-nav-cta {
  margin-top: 12px;
  width: 100%;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding: 48px 0 64px 0;
  position: relative;
  overflow: hidden;
}

@media (min-width: 768px) {
  .hero-section {
    padding: 72px 0 96px 0;
  }
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
}

@media (min-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1.05fr 1fr;
    gap: 48px;
  }
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.hero-tagline-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  border-radius: 9999px;
  background: rgba(13, 32, 56, 0.9);
  border: 1px solid var(--border-color);
  width: fit-content;
  max-width: 100%;
  font-size: 0.72rem;
  color: var(--primary);
  font-weight: 600;
  letter-spacing: 0.3px;
  white-space: nowrap;
}

.hero-title {
  font-size: clamp(1.75rem, 6.2vw, 3.25rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text-heading);
  word-break: break-word;
}

.hero-punchline {
  display: block;
  color: var(--primary);
  margin-top: 8px;
  font-size: 0.85em;
  background: linear-gradient(135deg, #F3F8FF 0%, #38BDF8 50%, #F5EA61 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--text-body);
  line-height: 1.7;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 8px;
}

.hero-features-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

@media (min-width: 640px) {
  .hero-features-list {
    grid-template-columns: repeat(4, 1fr);
  }
}

.hero-feature-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-body);
}

.hero-feature-icon {
  color: var(--accent-yellow);
  font-size: 1rem;
  flex-shrink: 0;
}

.hero-visual-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 16px;
  position: relative;
  box-shadow: var(--shadow-panel), var(--shadow-glow);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

@media (min-width: 768px) {
  .hero-visual-card {
    padding: 24px;
  }
}

.hero-svg-wrapper {
  width: 100%;
  max-width: 680px;
  aspect-ratio: 680 / 520;
}

/* ==========================================================================
   Section 1: 核心优势 (Core Advantages)
   ========================================================================== */
.advantages-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .advantages-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.advantage-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.advantage-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
  box-shadow: var(--shadow-glow);
}

.advantage-icon-box {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: rgba(14, 40, 74, 0.9);
  border: 1px solid rgba(56, 189, 248, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  flex-shrink: 0;
}

.advantage-icon-box svg {
  width: 28px;
  height: 28px;
}

.advantage-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-heading);
}

.advantage-text {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.65;
}

.advantage-highlights {
  list-style: none;
  margin-top: auto;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.85rem;
}

.advantage-highlights li {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
}

.advantage-highlights li span {
  color: var(--primary);
  font-weight: 600;
}

/* ==========================================================================
   Section 2: 全球网络 (Global Network Topology)
   ========================================================================== */
.network-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

@media (min-width: 1024px) {
  .network-layout {
    grid-template-columns: 1fr 1.15fr;
  }
}

.network-intro-panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.network-disclaimer-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: rgba(245, 234, 97, 0.1);
  border: 1px solid rgba(245, 234, 97, 0.3);
  color: var(--accent-yellow);
  font-size: 0.82rem;
  font-weight: 600;
  width: fit-content;
}

.network-metrics-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 8px 0;
}

.metric-item {
  background: var(--bg-alt);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px;
}

.metric-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.metric-value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-heading);
}

.metric-note {
  font-size: 0.75rem;
  color: var(--accent-yellow);
  margin-top: 4px;
}

.regions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.region-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: all var(--transition-fast);
}

.region-card:hover {
  border-color: var(--primary);
  background: var(--bg-card-hover);
}

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

.region-flag-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  color: var(--text-heading);
}

.region-flag {
  font-size: 1.25rem;
}

.region-badge {
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 9999px;
  background: rgba(56, 189, 248, 0.1);
  color: var(--primary);
  border: 1px solid rgba(56, 189, 248, 0.2);
}

.region-desc {
  font-size: 0.86rem;
  color: var(--text-body);
  line-height: 1.5;
}

.region-protocols {
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.region-protocols span {
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* ==========================================================================
   Section 3: AI 与流媒体 (AI Workstation & Streaming)
   ========================================================================== */
.ai-stream-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

@media (min-width: 1024px) {
  .ai-stream-layout {
    grid-template-columns: 1fr 1fr;
  }
}

.scenario-panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: relative;
  transition: border-color var(--transition-normal);
}

.scenario-panel:hover {
  border-color: rgba(56, 189, 248, 0.5);
}

.scenario-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  width: fit-content;
}

.scenario-badge.ai {
  background: rgba(245, 234, 97, 0.1);
  border: 1px solid rgba(245, 234, 97, 0.3);
  color: var(--accent-yellow);
}

.scenario-badge.stream {
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  color: var(--primary);
}

.scenario-title {
  font-size: 1.5rem;
  color: var(--text-heading);
}

.scenario-text {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.65;
}

.platform-chips-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 8px 0;
}

.platform-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: var(--bg-alt);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-heading);
  transition: border-color var(--transition-fast);
}

.platform-chip:hover {
  border-color: var(--primary);
}

.chip-tag {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 400;
}

.compliance-notice-box {
  background: rgba(14, 40, 74, 0.6);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-yellow);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin-top: 32px;
  font-size: 0.88rem;
  line-height: 1.6;
  color: var(--text-body);
}

.compliance-notice-box strong {
  color: var(--text-heading);
}

/* ==========================================================================
   Section 4: 套餐价格 (Pricing Plans)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-bottom: 24px;
}

@media (min-width: 768px) {
  .pricing-grid {
    grid-template-columns: repeat(3, 1fr);
    align-items: stretch;
  }
}

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

.pricing-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
}

.pricing-card.featured {
  background: linear-gradient(180deg, #102B4C 0%, #0D2038 100%);
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-glow);
}

@media (min-width: 768px) {
  .pricing-card.featured {
    transform: scale(1.03);
  }
  .pricing-card.featured:hover {
    transform: scale(1.03) translateY(-4px);
  }
}

.featured-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #F5EA61 0%, #EAB308 100%);
  color: #071426;
  font-size: 0.78rem;
  font-weight: 800;
  padding: 4px 16px;
  border-radius: 9999px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  box-shadow: 0 2px 10px rgba(245, 234, 97, 0.4);
}

.plan-type {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  min-height: 42px;
}

.plan-price-wrap {
  margin: 20px 0 16px 0;
  padding: 16px 0;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.plan-traffic-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--primary);
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.3);
  padding: 4px 12px;
  border-radius: 9999px;
  margin-bottom: 12px;
  letter-spacing: 0.3px;
}

.plan-traffic-badge.highlight {
  color: var(--accent-yellow);
  background: rgba(245, 234, 97, 0.12);
  border-color: rgba(245, 234, 97, 0.4);
}

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

.price-currency {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--primary);
}

.pricing-card.featured .price-currency {
  color: var(--accent-yellow);
}

.price-number {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1;
  color: var(--text-heading);
  letter-spacing: -0.03em;
}

.price-period {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.plan-price-sub {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 8px;
  line-height: 1.5;
}

.plan-save-tag {
  display: inline-block;
  color: var(--accent-yellow);
  font-weight: 600;
}

.pricing-extra-tiers {
  margin-top: 32px;
  padding: 20px 24px;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

@media (min-width: 768px) {
  .pricing-extra-tiers {
    grid-template-columns: repeat(2, 1fr);
    align-items: center;
  }
}

.extra-tier-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.extra-tier-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-heading);
  display: flex;
  align-items: center;
  gap: 8px;
}

.extra-tier-desc {
  font-size: 0.84rem;
  color: var(--text-body);
}

.plan-features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 28px;
  font-size: 0.9rem;
}

.plan-features-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  color: var(--text-body);
}

.check-icon {
  color: var(--primary);
  flex-shrink: 0;
  font-size: 1rem;
  margin-top: 2px;
}

.pricing-btn {
  margin-top: auto;
  width: 100%;
}

.pricing-footnote {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 24px auto 0 auto;
}

/* ==========================================================================
   Section 5: 9 篇独立 SEO 文章 (SEO Articles Grid)
   ========================================================================== */
.articles-section {
  background: rgba(11, 28, 51, 0.4);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.articles-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

@media (min-width: 640px) {
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .articles-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.article-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
  text-decoration: none;
}

.article-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary);
  box-shadow: var(--shadow-glow);
}

.article-cover {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #0E284A;
  border-bottom: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

.article-cover svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.article-card:hover .article-cover svg {
  transform: scale(1.05);
}

.article-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-meta-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  font-size: 0.78rem;
}

.article-category {
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  background: rgba(56, 189, 248, 0.12);
  color: var(--primary);
  font-weight: 600;
}

.article-readtime {
  color: var(--text-muted);
}

.article-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-heading);
  line-height: 1.45;
  margin-bottom: 10px;
}

.article-card:hover .article-card-title {
  color: var(--primary);
}

.article-excerpt {
  font-size: 0.88rem;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card-footer {
  margin-top: auto;
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
}

.article-date {
  color: var(--text-muted);
}

.article-read-more {
  color: var(--primary);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ==========================================================================
   Section 6: 用户评价 (User Reviews)
   ========================================================================== */
.reviews-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .reviews-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.review-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
}

.review-tag-placeholder {
  display: inline-block;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  background: rgba(245, 234, 97, 0.1);
  border: 1px solid rgba(245, 234, 97, 0.25);
  color: var(--accent-yellow);
  font-size: 0.75rem;
  font-weight: 600;
  width: fit-content;
}

.review-quote {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.65;
  font-style: italic;
}

.reviewer-profile {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: auto;
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
}

.reviewer-avatar {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: #1B355A;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-weight: 700;
  font-size: 0.85rem;
}

.reviewer-meta {
  display: flex;
  flex-direction: column;
}

.reviewer-role {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-heading);
}

.reviewer-scenario {
  font-size: 0.76rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Section 7: 常见问题 FAQ (details / summary)
   ========================================================================== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 860px;
  margin: 0 auto;
}

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

.faq-item:hover,
.faq-item[open] {
  border-color: var(--primary);
}

.faq-summary {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-heading);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  list-style: none;
  user-select: none;
}

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-chevron {
  width: 18px;
  height: 18px;
  color: var(--primary);
  flex-shrink: 0;
  transition: transform var(--transition-normal);
}

.faq-item[open] .faq-chevron {
  transform: rotate(180deg);
}

.faq-content {
  padding: 0 24px 24px 24px;
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.7;
  border-top: 1px solid rgba(32, 61, 90, 0.4);
  padding-top: 16px;
}

.faq-content p {
  margin-bottom: 0.8rem;
}

.faq-content ul, .faq-content ol {
  padding-left: 20px;
  margin-bottom: 0.8rem;
}

/* ==========================================================================
   Footer Component & Styling
   ========================================================================== */
.site-footer {
  background: #040E1B;
  border-top: 1px solid var(--border-color);
  padding: 64px 0 32px 0;
  font-size: 0.9rem;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

@media (min-width: 768px) {
  .footer-top-grid {
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
  }
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-brand-desc {
  font-size: 0.86rem;
  color: var(--text-muted);
  line-height: 1.65;
}

.footer-heading {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-heading);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
}

.footer-links-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links-list a {
  color: var(--text-body);
  font-size: 0.88rem;
  transition: color var(--transition-fast);
}

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

.footer-partners-bar {
  padding: 20px;
  border-radius: var(--radius-md);
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  margin-bottom: 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

@media (min-width: 768px) {
  .footer-partners-bar {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

.partners-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-heading);
}

.partners-links-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
}

.partner-item-link {
  font-size: 0.85rem;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 16px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    text-align: left;
  }
}

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

.footer-legal-links a {
  color: var(--text-muted);
}

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

/* ==========================================================================
   Article Page Specific Styling
   ========================================================================== */
.article-header {
  padding: 48px 0 32px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 40px;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.breadcrumbs a {
  color: var(--text-body);
}

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

.breadcrumbs-sep {
  color: var(--border-color);
}

.article-title-hero {
  font-size: 2.1rem;
  font-weight: 800;
  color: var(--text-heading);
  line-height: 1.3;
  margin-bottom: 16px;
}

@media (min-width: 768px) {
  .article-title-hero {
    font-size: 2.75rem;
  }
}

.article-meta-hero {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.article-content-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  margin-bottom: 64px;
}

@media (min-width: 1024px) {
  .article-content-layout {
    grid-template-columns: 1fr 300px;
  }
}

.article-main-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-body);
}

.article-main-content h2 {
  font-size: 1.7rem;
  margin: 40px 0 16px 0;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-heading);
}

.article-main-content h3 {
  font-size: 1.3rem;
  margin: 28px 0 12px 0;
  color: var(--text-heading);
}

.article-main-content p {
  margin-bottom: 1.25rem;
}

.article-main-content ul, 
.article-main-content ol {
  padding-left: 24px;
  margin-bottom: 1.5rem;
}

.article-main-content li {
  margin-bottom: 0.5rem;
}

.article-callout {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 24px 0;
}

.article-callout.warning {
  border-left-color: var(--accent-yellow);
}

.article-callout-title {
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.table-wrapper {
  overflow-x: auto;
  margin: 24px 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

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

th, td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
}

th {
  background: var(--bg-panel);
  color: var(--text-heading);
  font-weight: 700;
}

tr:nth-child(even) {
  background: rgba(14, 40, 74, 0.3);
}

/* Sidebar & Table of Contents */
.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.sidebar-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  position: sticky;
  top: 96px;
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 16px;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 0.88rem;
}

.toc-list a {
  color: var(--text-body);
  display: block;
}

.toc-list a:hover {
  color: var(--primary);
}

/* Related Articles Block */
.related-articles-section {
  padding-top: 48px;
  border-top: 1px solid var(--border-color);
  margin-top: 48px;
}

.related-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 24px;
}

@media (min-width: 640px) {
  .related-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .related-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Reduced Motion Override */
@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;
  }
}