/* ==========================================================================
   BoostNet - Stealth OLED True-Black Luxury UI Stylesheet
   Pitch Obsidian Darkness (#000000) | Deep Slate Surfaces (#0a0a0c)
   Hairline Graphite Borders (#1c1d22) | Surgical Cold-White Luminescence
   Flashlight Shader Micro-Interactions | Swiss Monospace Alignment Marks
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&display=swap');

/* --- Root & Theme Variables --- */
:root {
  /* Brand Accents */
  --accent-cyan: #38bdf8;
  --accent-blue: #2563eb;
  --accent-cold-white: #ffffff;
  --photon-glow: rgba(255, 255, 255, 0.95);
  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.25);

  /* Light Theme (Default: Architectural Minimalist Swiss) */
  --bg-page: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f1f5f9;
  --bg-surface-subtle: #f8fafc;
  --bg-badge: rgba(15, 23, 42, 0.05);

  --text-main: #090d16;
  --text-muted: #475569;
  --text-subtle: #94a3b8;
  --text-inverse: #ffffff;

  --border-color: #e2e8f0;
  --border-hairline: #cbd5e1;
  --border-active: #090d16;
  --crosshair-color: #94a3b8;

  --header-bg: rgba(255, 255, 255, 0.82);
  --header-border: rgba(226, 232, 240, 0.85);

  --card-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.04);
  --card-shadow-hover: 0 12px 30px -4px rgba(0, 0, 0, 0.08);

  --spotlight-color: rgba(15, 23, 42, 0.03);
  --btn-theme-bg: rgba(15, 23, 42, 0.05);
  --btn-theme-border: rgba(15, 23, 42, 0.12);
  --btn-theme-hover-bg: rgba(15, 23, 42, 0.08);

  --cta-btn-bg: #090d16;
  --cta-btn-text: #ffffff;
  --cta-btn-hover: #1e293b;

  --transition-smooth: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, Consolas, monospace;
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --container-width: 1220px;
}

/* Dark Theme: Stealth OLED True-Black Luxury UI */
[data-theme="dark"] {
  --bg-page: #000000;              /* Pitch obsidian darkness */
  --bg-surface: #0a0a0c;           /* Deep slate surface */
  --bg-surface-elevated: #111215;  /* Stealth elevated surface */
  --bg-surface-subtle: #060608;    /* Dark void boundary */
  --bg-badge: rgba(255, 255, 255, 0.04);

  --text-main: #f8fafc;            /* Surgical cold-white luminescence */
  --text-muted: #8e95a5;
  --text-subtle: #525866;
  --text-inverse: #000000;

  --border-color: #1c1d22;         /* Refined hairline graphite border */
  --border-hairline: #272930;
  --border-active: #ffffff;
  --crosshair-color: #3f434d;

  --header-bg: rgba(0, 0, 0, 0.85);
  --header-border: rgba(28, 29, 34, 0.9);

  --card-shadow: 0 0 0 1px #1c1d22;
  --card-shadow-hover: 0 0 35px -5px rgba(255, 255, 255, 0.06), 0 0 0 1px rgba(255, 255, 255, 0.22);

  --spotlight-color: rgba(255, 255, 255, 0.07);
  --btn-theme-bg: rgba(255, 255, 255, 0.05);
  --btn-theme-border: rgba(255, 255, 255, 0.12);
  --btn-theme-hover-bg: rgba(255, 255, 255, 0.1);

  --cta-btn-bg: #ffffff;
  --cta-btn-text: #000000;
  --cta-btn-hover: #e2e8f0;
}

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

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  scroll-behavior: smooth;
  scroll-padding-top: 84px; /* Dynamic offset for sticky header */
  background-color: var(--bg-page);
  color: var(--text-main);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-page);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background-color var(--transition-smooth), color var(--transition-smooth);
}

/* Subtle carbon grain texture backdrop on dark OLED */
[data-theme="dark"] body {
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(255, 255, 255, 0.02) 0%, transparent 60%),
    linear-gradient(rgba(28, 29, 34, 0.15) 1px, transparent 1px),
    linear-gradient(90deg, rgba(28, 29, 34, 0.15) 1px, transparent 1px);
  background-size: 100% 100%, 48px 48px, 48px 48px;
  background-position: 0 0, -1px -1px, -1px -1px;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-smooth);
}

img, svg {
  vertical-align: middle;
  max-width: 100%;
}

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
  color: inherit;
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 28px;
  padding-right: 28px;
}

/* Monospace Telemetry Badges */
.mono-badge {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  border-radius: var(--radius-xs);
  background: var(--bg-badge);
  border: 1px solid var(--border-color);
}

.mono-indicator {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--success);
  box-shadow: 0 0 8px var(--success-glow);
  display: inline-block;
  animation: pulse-telemetry 2.4s infinite;
}

@keyframes pulse-telemetry {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.35; transform: scale(0.85); }
}

/* Microscopic Corner Crosshairs */
.crosshair-corner {
  position: absolute;
  width: 7px;
  height: 7px;
  pointer-events: none;
  z-index: 2;
}

.crosshair-corner::before, .crosshair-corner::after {
  content: "";
  position: absolute;
  background: var(--crosshair-color);
}

.crosshair-tl { top: -1px; left: -1px; }
.crosshair-tl::before { top: 0; left: 0; width: 7px; height: 1px; }
.crosshair-tl::after { top: 0; left: 0; width: 1px; height: 7px; }

.crosshair-tr { top: -1px; right: -1px; }
.crosshair-tr::before { top: 0; right: 0; width: 7px; height: 1px; }
.crosshair-tr::after { top: 0; right: 0; width: 1px; height: 7px; }

.crosshair-bl { bottom: -1px; left: -1px; }
.crosshair-bl::before { bottom: 0; left: 0; width: 7px; height: 1px; }
.crosshair-bl::after { bottom: 0; left: 0; width: 1px; height: 7px; }

.crosshair-br { bottom: -1px; right: -1px; }
.crosshair-br::before { bottom: 0; right: 0; width: 7px; height: 1px; }
.crosshair-br::after { bottom: 0; right: 0; width: 1px; height: 7px; }

/* --- Site Header & Navigation --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--header-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--header-border);
  transition: background-color var(--transition-smooth), border-color var(--transition-smooth);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

/* Brand Logo */
.brand-logo {
  display: flex;
  align-items: center;
  line-height: 1;
  text-decoration: none;
}

.brand-logo-img {
  height: 38px;
  width: auto;
  display: block;
  object-fit: contain;
}

.footer-logo-img {
  height: 32px;
  width: auto;
  display: block;
  object-fit: contain;
}

/* Theme Switching for Logo */
.logo-light {
  display: block;
}

.logo-dark {
  display: none;
}

[data-theme="dark"] .logo-light {
  display: none;
}

[data-theme="dark"] .logo-dark {
  display: block;
}

/* Navigation Menu */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.04em;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  padding: 6px 4px;
  transition: color 0.2s ease;
}

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--text-main);
  transition: width 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* Highlight badge for "推荐资讯" entry in navbar */
.nav-link-special {
  color: var(--accent-cyan);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.nav-link-special::before {
  content: "NEW";
  font-size: 0.65rem;
  padding: 1px 5px;
  border-radius: 3px;
  background: rgba(56, 189, 248, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.35);
  color: var(--accent-cyan);
  font-weight: 700;
}

.nav-link-special:hover {
  color: #7dd3fc;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* Delicate, Frosted Day/Night Toggle Button */
.theme-toggle-btn {
  position: relative;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-xs);
  background: var(--btn-theme-bg);
  border: 1px solid var(--btn-theme-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-smooth);
  outline: none;
}

.theme-toggle-btn:hover {
  background: var(--btn-theme-hover-bg);
  border-color: var(--border-active);
  transform: translateY(-1px);
}

.theme-toggle-btn svg {
  width: 18px;
  height: 18px;
  stroke-width: 2;
  stroke: currentColor;
  fill: none;
  transition: transform 0.4s ease;
}

.icon-sun { display: block; }
.icon-moon { display: none; }

[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* Mobile Menu Button */
.mobile-menu-btn {
  display: none;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  background: var(--btn-theme-bg);
  border: 1px solid var(--btn-theme-border);
  border-radius: var(--radius-xs);
  color: var(--text-main);
}

.mobile-menu-btn svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  stroke-width: 2;
}

/* Surgical Stealth CTA Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--cta-btn-bg);
  color: var(--cta-btn-text) !important;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.88rem;
  letter-spacing: 0.04em;
  padding: 10px 22px;
  border-radius: var(--radius-xs);
  border: 1px solid transparent;
  transition: all var(--transition-smooth);
  white-space: nowrap;
}

.btn-primary:hover {
  background: var(--cta-btn-hover);
  border-color: var(--border-active);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(255, 255, 255, 0.12);
}

.btn-lg {
  padding: 14px 32px;
  font-size: 0.98rem;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: transparent;
  color: var(--text-main);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-weight: 550;
  font-size: 0.88rem;
  letter-spacing: 0.04em;
  padding: 10px 22px;
  border-radius: var(--radius-xs);
  transition: all var(--transition-smooth);
}

.btn-secondary:hover {
  background: var(--bg-surface-elevated);
  border-color: var(--border-hairline);
  transform: translateY(-1px);
}

.stealth-card {
  position: relative;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 32px 28px;
  overflow: visible; /* Prevent clipping of badges and corner crosshairs */
  transition: border-color var(--transition-smooth), transform var(--transition-smooth), box-shadow var(--transition-smooth);
  box-shadow: var(--card-shadow);
}

/* Flashlight ambient illumination layer */
.stealth-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(
    480px circle at var(--mouse-x, -999px) var(--mouse-y, -999px),
    var(--spotlight-color),
    transparent 50%
  );
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
  z-index: 1;
}

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

/* Razor-sharp cold-white photon pulse border on hover */
.stealth-card:hover {
  border-color: rgba(255, 255, 255, 0.4);
  transform: translateY(-3px);
  box-shadow: var(--card-shadow-hover);
}

[data-theme="light"] .stealth-card:hover {
  border-color: #090d16;
}

/* --- Hero Section --- */
.hero-section {
  position: relative;
  padding: 90px 0 70px;
  border-bottom: 1px solid var(--border-color);
  overflow: hidden;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 960px;
  margin: 0 auto;
}

.hero-brand-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 850;
  line-height: 1.15;
  letter-spacing: -0.04em;
  color: var(--text-main);
  margin-bottom: 24px;
}

.hero-title span.brand-luminescence {
  color: var(--text-main);
  text-shadow: 0 0 24px rgba(255, 255, 255, 0.45);
  border-bottom: 2px solid var(--border-active);
  padding-bottom: 2px;
}

[data-theme="light"] .hero-title span.brand-luminescence {
  text-shadow: none;
  border-bottom: 2px solid #090d16;
}

.hero-brief {
  font-size: 1.2rem;
  line-height: 1.7;
  color: var(--text-muted);
  margin-bottom: 42px;
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
  font-weight: 400;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 38px;
}

.hero-telemetry-strip {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-subtle);
  letter-spacing: 0.05em;
}

.hero-telemetry-item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.hero-telemetry-item svg {
  width: 14px;
  height: 14px;
  stroke: var(--success);
}

/* Hero Telemetry Visual Grid */
.hero-telemetry-board {
  margin-top: 56px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  position: relative;
}

.telemetry-tile {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  padding: 22px 18px;
  text-align: left;
  position: relative;
  transition: all var(--transition-smooth);
}

.telemetry-tile:hover {
  border-color: var(--border-hairline);
  background: var(--bg-surface-elevated);
}

.tile-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-subtle);
  letter-spacing: 0.06em;
}

.tile-value {
  font-family: var(--font-mono);
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.15;
  margin-bottom: 4px;
  letter-spacing: -0.02em;
}

.tile-label {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* --- Section Global Structure --- */
.section-padding {
  padding: 96px 0;
  position: relative;
}

.section-padding:not(:last-child) {
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  max-width: 760px;
  margin: 0 auto 56px;
  text-align: center;
  position: relative;
}

.section-code-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-subtle);
  margin-bottom: 12px;
  display: inline-block;
}

.section-title {
  font-size: 2.3rem;
  font-weight: 850;
  letter-spacing: -0.03em;
  line-height: 1.25;
  color: var(--text-main);
  margin-bottom: 14px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* --- Core Advantages (3 Cards) --- */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.advantage-card {
  display: flex;
  flex-direction: column;
}

.advantage-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-subtle);
  margin-bottom: 20px;
  letter-spacing: 0.06em;
}

.advantage-icon-frame {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-xs);
  border: 1px solid var(--border-hairline);
  background: var(--bg-surface-elevated);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-main);
  margin-bottom: 22px;
}

.advantage-icon-frame svg {
  width: 24px;
  height: 24px;
  stroke: currentColor;
  stroke-width: 1.8;
  fill: none;
}

.advantage-title {
  font-size: 1.35rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 14px;
  letter-spacing: -0.02em;
}

.advantage-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 24px;
  flex-grow: 1;
}

.advantage-telemetry-list {
  border-top: 1px solid var(--border-color);
  padding-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-muted);
}

.advantage-telemetry-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.advantage-telemetry-row svg {
  width: 14px;
  height: 14px;
  stroke: var(--success);
  flex-shrink: 0;
}

/* --- Streaming Media & AI Unlock Cards --- */
.streaming-grid, .ai-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.matrix-card {
  display: flex;
  flex-direction: column;
  position: relative;
}

.matrix-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.matrix-logo-box {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-xs);
  border: 1px solid var(--border-color);
  background: var(--bg-surface-elevated);
  display: flex;
  align-items: center;
  justify-content: center;
}

.matrix-logo-box svg {
  width: 24px;
  height: 24px;
}

.matrix-status-pill {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 3px 8px;
  border-radius: var(--radius-xs);
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #10b981;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.matrix-card-title {
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}

.matrix-card-desc {
  font-size: 0.86rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 18px;
}

.matrix-telemetry-footer {
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-subtle);
  border-top: 1px dashed var(--border-color);
  padding-top: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* --- Real Market Pricing Comparison Table --- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
  padding-top: 18px; /* Headroom so floating tag is never obscured by parent */
}

.pricing-card {
  display: flex;
  flex-direction: column;
  position: relative;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 42px 30px 38px;
  overflow: visible !important; /* Critical: Prevent clipping of top badge */
}

.pricing-card.featured {
  border: 1px solid rgba(255, 255, 255, 0.45);
  background-color: var(--bg-surface-elevated);
  box-shadow: 0 0 40px -10px rgba(255, 255, 255, 0.08);
  overflow: visible !important;
}

[data-theme="light"] .pricing-card.featured {
  border: 2px solid #090d16;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.06);
  overflow: visible !important;
}

.featured-telemetry-tag {
  position: absolute;
  top: -14px;
  left: 24px;
  background: var(--cta-btn-bg);
  color: var(--cta-btn-text);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: var(--radius-xs);
  text-transform: uppercase;
  z-index: 20;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
  border: 1px solid var(--border-hairline);
  line-height: 1.3;
}

.plan-telemetry-header {
  margin-bottom: 22px;
}

.plan-tier-code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-subtle);
  letter-spacing: 0.08em;
  margin-bottom: 4px;
}

.plan-tier-name {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.02em;
  margin-bottom: 6px;
}

.plan-tier-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.plan-pricing-block {
  padding: 22px 0;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 26px;
}

.price-currency {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-main);
  margin-right: 2px;
}

.price-val {
  font-family: var(--font-mono);
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--text-main);
  line-height: 1;
}

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

.plan-specs-list {
  display: flex;
  flex-direction: column;
  gap: 13px;
  margin-bottom: 32px;
  flex-grow: 1;
}

.spec-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--text-muted);
}

.spec-item.highlighted {
  color: var(--text-main);
  font-weight: 600;
}

.spec-item svg {
  width: 16px;
  height: 16px;
  stroke: var(--success);
  flex-shrink: 0;
}

.pricing-card .btn-primary, .pricing-card .btn-secondary {
  width: 100%;
}

/* --- Testimonials Section --- */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  display: flex;
  flex-direction: column;
}

.review-telemetry {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-subtle);
  margin-bottom: 16px;
}

.star-rating-row {
  display: flex;
  gap: 3px;
  color: #f59e0b;
}

.star-rating-row svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

.review-quote {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 24px;
  flex-grow: 1;
}

.reviewer-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

.reviewer-avatar-box {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-xs);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-hairline);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-main);
}

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

.reviewer-name {
  font-size: 0.94rem;
  font-weight: 700;
  color: var(--text-main);
}

.reviewer-title {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--text-subtle);
}

/* --- FAQ Section --- */
.faq-container {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-row {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  overflow: hidden;
  transition: border-color var(--transition-smooth);
}

.faq-row:hover {
  border-color: var(--border-hairline);
}

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

.faq-trigger-prefix {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-subtle);
  margin-right: 12px;
}

.faq-chevron {
  width: 18px;
  height: 18px;
  stroke: var(--text-subtle);
  transition: transform 0.3s ease;
  flex-shrink: 0;
}

.faq-row.active .faq-chevron {
  transform: rotate(180deg);
  stroke: var(--text-main);
}

.faq-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease-out, padding 0.35s ease-out;
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.94rem;
  line-height: 1.75;
}

.faq-row.active .faq-body {
  max-height: 320px;
  padding-bottom: 22px;
}

/* --- Bottom Stealth Banner --- */
.stealth-banner {
  margin: 80px 0 30px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 60px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.stealth-banner-content {
  position: relative;
  z-index: 2;
  max-width: 680px;
  margin: 0 auto;
}

.stealth-banner h2 {
  font-size: 2.3rem;
  font-weight: 850;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 14px;
}

.stealth-banner p {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 32px;
}

/* --- Site Footer --- */
/* Strictly ONLY 4 titles: 网站地图, 关于我们, 服务条款, 隐私政策 */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 48px 0;
  margin-top: auto;
  transition: background-color var(--transition-smooth), border-color var(--transition-smooth);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 26px;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 36px;
}

.footer-link {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition-smooth);
}

.footer-link:hover {
  color: var(--text-main);
}

.footer-copyright {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--text-subtle);
  text-align: center;
}

/* --- Auxiliary Subpages (about, terms, privacy, sitemap, insights) --- */
.subpage-hero {
  padding: 64px 0 44px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-surface-subtle);
}

.subpage-title {
  font-size: 2.6rem;
  font-weight: 850;
  color: var(--text-main);
  letter-spacing: -0.035em;
  margin-bottom: 12px;
}

.subpage-desc {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto;
}

.subpage-body {
  padding: 64px 0 96px;
  max-width: 920px;
  margin: 0 auto;
}

.article-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 38px;
  margin-bottom: 28px;
  position: relative;
}

.article-card h2 {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: -0.02em;
}

.article-card h2 svg {
  width: 22px;
  height: 22px;
  stroke: var(--text-main);
}

.article-card p {
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.8;
  margin-bottom: 16px;
}

.article-card p:last-child {
  margin-bottom: 0;
}

.article-card ul {
  list-style: disc;
  margin-left: 24px;
  margin-bottom: 18px;
  color: var(--text-muted);
  line-height: 1.75;
}

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

/* Insights Articles Layout */
.insights-feed {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.insight-post {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 34px;
  transition: all var(--transition-smooth);
  position: relative;
}

.insight-post:hover {
  border-color: var(--border-hairline);
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-2px);
}

.insight-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--text-subtle);
  margin-bottom: 12px;
  letter-spacing: 0.05em;
}

.insight-tag {
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.1);
  padding: 2px 8px;
  border-radius: var(--radius-xs);
  border: 1px solid rgba(56, 189, 248, 0.25);
}

.insight-title {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  letter-spacing: -0.02em;
  line-height: 1.35;
}

.insight-summary {
  font-size: 0.96rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 18px;
}

/* Sitemap Grid */
.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.sitemap-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  padding: 28px;
}

.sitemap-box h3 {
  font-size: 1.15rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 18px;
}

.sitemap-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sitemap-link {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.sitemap-link:hover {
  color: var(--text-main);
  text-decoration: underline;
}

/* --- Responsive Media Queries (@media) --- */
@media (max-width: 1080px) {
  .hero-title {
    font-size: 2.9rem;
  }
  .advantages-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .streaming-grid, .ai-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 540px;
    margin: 0 auto;
  }
  .testimonials-grid {
    grid-template-columns: 1fr;
  }
  .hero-telemetry-board {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 1024px) {
  .site-header {
    height: 68px;
  }
  .header-inner {
    height: 68px;
  }
  .mobile-menu-btn {
    display: flex;
  }
  .nav-menu {
    position: fixed;
    top: 68px;
    left: 0;
    width: 100%;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    padding: 24px;
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
    display: none;
    box-shadow: 0 20px 30px rgba(0, 0, 0, 0.4);
    z-index: 999;
  }
  .nav-menu.active {
    display: flex;
  }
  .nav-link {
    font-size: 0.96rem;
    width: 100%;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
  }
  .header-actions .btn-primary {
    display: none;
  }
  .hero-section {
    padding: 60px 0 45px;
  }
  .hero-title {
    font-size: 2.2rem;
  }
  .hero-brief {
    font-size: 1.05rem;
    margin-bottom: 32px;
  }
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta-group .btn-lg {
    width: 100%;
  }
  .hero-telemetry-strip {
    flex-direction: column;
    gap: 12px;
  }
  .hero-telemetry-board {
    grid-template-columns: 1fr;
  }
  .streaming-grid, .ai-grid {
    grid-template-columns: 1fr;
  }
  .section-padding {
    padding: 64px 0;
  }
  .section-title {
    font-size: 1.85rem;
  }
  .stealth-banner {
    padding: 40px 20px;
  }
  .stealth-banner h2 {
    font-size: 1.8rem;
  }
  .footer-nav {
    gap: 20px;
    flex-direction: column;
  }
  .sitemap-grid {
    grid-template-columns: 1fr;
  }
  .article-card {
    padding: 24px 18px;
  }
  .insight-post {
    padding: 24px 18px;
  }
  .article-related-grid {
    grid-template-columns: 1fr !important;
  }
}

/* ==========================================================================
   Long-form SEO Article Components (TOC, FAQ, Related Reading, Breadcrumbs)
   ========================================================================== */

.article-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 24px 90px;
}

.article-breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-subtle);
  margin-bottom: 24px;
}

.article-breadcrumb a:hover {
  color: var(--text-main);
  text-decoration: underline;
}

.article-breadcrumb span.sep {
  opacity: 0.5;
}

.article-header {
  margin-bottom: 36px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.article-post-title {
  font-size: 2.35rem;
  font-weight: 850;
  line-height: 1.25;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 18px;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-subtle);
}

.article-meta-badge {
  background: var(--bg-badge);
  border: 1px solid var(--border-color);
  padding: 3px 10px;
  border-radius: var(--radius-xs);
  color: var(--accent-cyan);
}

/* Table of Contents (TOC) */
.article-toc {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 24px 28px;
  margin-bottom: 40px;
  position: relative;
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.86rem;
}

.toc-list li {
  line-height: 1.5;
}

.toc-list a {
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.toc-list a:hover {
  color: var(--text-main);
  text-decoration: underline;
}

/* Article Body Typography */
.article-content {
  color: var(--text-muted);
  font-size: 1.02rem;
  line-height: 1.85;
}

.article-content h2 {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--text-main);
  margin-top: 48px;
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
  letter-spacing: -0.02em;
}

.article-content h3 {
  font-size: 1.3rem;
  font-weight: 750;
  color: var(--text-main);
  margin-top: 32px;
  margin-bottom: 14px;
}

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

.article-content ul, .article-content ol {
  margin-left: 24px;
  margin-bottom: 22px;
}

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

.article-content strong {
  color: var(--text-main);
}

.article-content blockquote {
  border-left: 3px solid var(--border-active);
  padding: 14px 20px;
  background: var(--bg-surface-elevated);
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
  margin: 24px 0;
  font-size: 0.96rem;
  color: var(--text-muted);
}

/* Internal links */
.internal-link {
  color: var(--accent-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 600;
  transition: color 0.2s ease;
}

.internal-link:hover {
  color: #7dd3fc;
}

/* Technical Callout Boxes */
.tech-callout {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-cyan);
  padding: 20px 22px;
  border-radius: var(--radius-xs);
  margin: 28px 0;
  font-size: 0.94rem;
}

.tech-callout-header {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--accent-cyan);
  margin-bottom: 8px;
  text-transform: uppercase;
}

/* Article In-line CTA Banner */
.article-cta-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 32px 28px;
  text-align: center;
  margin: 44px 0;
}

.article-cta-box h3 {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 10px;
}

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

/* Article FAQ Block */
.article-faq-section {
  margin-top: 50px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.article-faq-title {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 24px;
}

.faq-qa-item {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  padding: 20px 22px;
  margin-bottom: 16px;
}

.faq-q {
  font-size: 1.05rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.faq-q-prefix {
  font-family: var(--font-mono);
  color: var(--accent-cyan);
  font-size: 0.9rem;
}

.faq-a {
  font-size: 0.94rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* Related Reading Section */
.article-related-section {
  margin-top: 54px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.article-related-title {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 20px;
}

.article-related-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.related-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  padding: 20px 18px;
  transition: all var(--transition-smooth);
}

.related-card:hover {
  border-color: var(--border-hairline);
  transform: translateY(-2px);
  box-shadow: var(--card-shadow-hover);
}

.related-card-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent-cyan);
  margin-bottom: 6px;
}

.related-card-title {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.45;
}