/* ==========================================================================
   iKuuu VPN - Distributed Photon-Swarm Void-Network UI Layout
   Palette: True OLED Black (#000000), Cryogenic Cyan (#22d3ee), Deep Nebula Violet (#6366f1), Starlight White (#ffffff)
   Pure Vanilla CSS - Zero Heavy Frameworks - Blazing Instant Load
   ========================================================================== */

/* --- 1. Design Tokens & Theme Variables --- */
:root {
  /* Light Theme (Default Daylight Mode) */
  --bg-void: #f8fafc;
  --bg-primary: #ffffff;
  --bg-secondary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(255, 255, 255, 0.98);
  --bg-telemetry: rgba(248, 250, 252, 0.88);
  --bg-glass: rgba(255, 255, 255, 0.82);
  --bg-glass-subtle: rgba(255, 255, 255, 0.55);

  --text-primary: #090d16;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-starlight: #ffffff;

  --color-cyan: #0891b2;
  --color-cyan-glow: rgba(8, 145, 178, 0.25);
  --color-cyan-badge: rgba(8, 145, 178, 0.1);

  --color-violet: #6366f1;
  --color-violet-glow: rgba(99, 102, 241, 0.25);
  
  --accent-gradient: linear-gradient(135deg, #4f46e5 0%, #06b6d4 100%);
  --accent-gradient-glow: rgba(79, 70, 229, 0.28);
  --accent-gradient-text: linear-gradient(135deg, #4338ca 0%, #0891b2 50%, #7c3aed 100%);

  --border-light: rgba(226, 232, 240, 0.85);
  --border-telemetry: rgba(8, 145, 178, 0.2);
  --border-card: #e2e8f0;
  --border-highlight: rgba(99, 102, 241, 0.35);

  --color-success: #10b981;
  --color-success-bg: rgba(16, 185, 129, 0.1);
  --color-warning: #f59e0b;

  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 16px -2px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.08);
  --shadow-glow: 0 0 35px rgba(8, 145, 178, 0.2);
  --shadow-telemetry: 0 16px 36px -10px rgba(0, 0, 0, 0.08);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  --transition-fast: 0.18s ease;
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-smooth: 0.5s cubic-bezier(0.16, 1, 0.3, 1);

  --nav-height: 74px;
  --max-width: 1240px;

  --canvas-particle-color: rgba(79, 70, 229, 0.6);
  --canvas-line-color: rgba(6, 182, 212, 0.2);
}

/* Dark Theme - Distributed Photon-Swarm Dark UI (True OLED Black & Void Network) */
[data-theme="dark"] {
  --bg-void: #000000;
  --bg-primary: #020408;
  --bg-secondary: #060913;
  --bg-card: rgba(8, 12, 24, 0.75);
  --bg-card-hover: rgba(13, 20, 38, 0.9);
  --bg-telemetry: rgba(4, 8, 18, 0.78);
  --bg-glass: rgba(2, 4, 8, 0.85);
  --bg-glass-subtle: rgba(15, 23, 42, 0.5);

  --text-primary: #ffffff;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-starlight: #ffffff;

  --color-cyan: #22d3ee;
  --color-cyan-glow: rgba(34, 211, 238, 0.4);
  --color-cyan-badge: rgba(34, 211, 238, 0.12);

  --color-violet: #6366f1;
  --color-violet-glow: rgba(99, 102, 241, 0.45);

  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #22d3ee 100%);
  --accent-gradient-glow: rgba(34, 211, 238, 0.35);
  --accent-gradient-text: linear-gradient(135deg, #ffffff 0%, #22d3ee 50%, #818cf8 100%);

  --border-light: rgba(255, 255, 255, 0.07);
  --border-telemetry: rgba(34, 211, 238, 0.22);
  --border-card: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(34, 211, 238, 0.4);

  --color-success: #34d399;
  --color-success-bg: rgba(52, 211, 153, 0.15);
  --color-warning: #fbbf24;

  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.6);
  --shadow-md: 0 10px 25px -3px rgba(0, 0, 0, 0.7);
  --shadow-lg: 0 25px 35px -5px rgba(0, 0, 0, 0.8);
  --shadow-glow: 0 0 45px rgba(34, 211, 238, 0.25);
  --shadow-telemetry: 0 20px 50px rgba(0, 0, 0, 0.85);

  --canvas-particle-color: rgba(34, 211, 238, 0.85);
  --canvas-line-color: rgba(99, 102, 241, 0.3);
}

/* --- 2. Base & Typography Reset --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-void);
  color: var(--text-primary);
  line-height: 1.68;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  position: relative;
}

/* Photon Particle Interactive Swarm Canvas */
#swarm-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  opacity: 0.88;
  transition: opacity var(--transition-normal);
}

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

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

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

ul, ol {
  list-style: none;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 28px;
  padding-right: 28px;
  position: relative;
  z-index: 2;
}

/* Typography Helpers */
.gradient-text {
  background: var(--accent-gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  font-weight: 900;
}

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

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  background: var(--color-cyan-badge);
  color: var(--color-cyan);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
  border: 1px solid var(--border-telemetry);
  backdrop-filter: blur(8px);
}

.section-title {
  font-size: 2.35rem;
  font-weight: 850;
  line-height: 1.25;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: -0.025em;
}

.section-desc {
  font-size: 1.08rem;
  color: var(--text-secondary);
  line-height: 1.68;
}

/* Section Spacing */
.section {
  padding: 96px 0;
  position: relative;
  z-index: 2;
}

.section-alt {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

/* --- 3. Sticky Navigation Header --- */
.site-header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  z-index: 1000;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

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

.logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 900;
  font-size: 1.3rem;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.logo-badge {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 0 20px var(--accent-gradient-glow);
  position: relative;
  overflow: hidden;
}

.logo-img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 0 16px var(--color-cyan-glow);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
  background: #ffffff;
  display: block;
}

.logo-link:hover .logo-img {
  transform: scale(1.08) rotate(6deg);
  box-shadow: 0 0 24px var(--color-cyan-glow);
}

.logo-badge::after {
  content: "";
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent, rgba(255,255,255,0.3), transparent);
  transform: rotate(45deg);
  animation: shine 4s infinite;
}

@keyframes shine {
  0% { transform: translateX(-150%) rotate(45deg); }
  30%, 100% { transform: translateX(150%) rotate(45deg); }
}

.logo-text {
  font-weight: 900;
}

.logo-text span {
  color: var(--color-cyan);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 6px 4px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast);
}

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 100%;
  height: 2px;
  background: var(--accent-gradient);
  border-radius: 2px;
  transition: transform var(--transition-normal);
}

.nav-link:hover::after,
.nav-link.active::after {
  transform: translateX(-50%) scaleX(1);
}

/* Special Badge for '推荐资讯' in Nav */
.nav-link-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.nav-pill-tag {
  background: var(--color-cyan-badge);
  border: 1px solid var(--border-telemetry);
  color: var(--color-cyan);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: var(--radius-full);
  margin-left: 4px;
}

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

/* Translucent Glass Theme Switcher Button */
.theme-toggle-btn {
  position: relative;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-glass-subtle);
  border: 1px solid var(--border-telemetry);
  color: var(--text-secondary);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
  cursor: pointer;
  overflow: hidden;
}

.theme-toggle-btn:hover {
  background: var(--bg-card);
  border-color: var(--color-cyan);
  color: var(--text-primary);
  transform: translateY(-2px);
  box-shadow: 0 0 16px var(--color-cyan-glow);
}

.theme-icon-sun,
.theme-icon-moon {
  position: absolute;
  width: 20px;
  height: 20px;
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

:root .theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}
:root .theme-icon-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.4);
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.4);
}
[data-theme="dark"] .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: var(--color-cyan);
}

/* CTA Buttons */
.btn-cta-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: var(--radius-full);
  background: var(--accent-gradient);
  color: #ffffff !important;
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  box-shadow: 0 4px 18px var(--accent-gradient-glow);
  transition: all var(--transition-normal);
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-cta-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px var(--accent-gradient-glow), 0 0 15px var(--color-cyan-glow);
  filter: brightness(1.08);
}

.btn-cta-primary:active {
  transform: translateY(0);
}

.btn-cta-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--border-telemetry);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(14px);
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.btn-cta-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--color-cyan);
  color: var(--color-cyan);
  transform: translateY(-2px);
  box-shadow: 0 0 20px var(--color-cyan-glow);
}

.btn-large {
  padding: 15px 32px;
  font-size: 1.08rem;
}

.btn-block {
  width: 100%;
}

.mobile-toggle-btn {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  background: var(--bg-glass-subtle);
  border: 1px solid var(--border-telemetry);
}

/* --- 4. Hero Section & Smoked-Glass Telemetry Panes --- */
.hero-section {
  padding: 80px 0 96px 0;
  position: relative;
  overflow: hidden;
}

.hero-glow-nebula {
  position: absolute;
  top: -180px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 550px;
  background: radial-gradient(circle, var(--color-violet-glow) 0%, var(--color-cyan-glow) 40%, rgba(0,0,0,0) 75%);
  filter: blur(90px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.65;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 1160px;
  margin: 0 auto;
}

.hero-badge-swarm {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 20px;
  border-radius: var(--radius-full);
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  box-shadow: var(--shadow-telemetry);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--color-cyan);
  margin-bottom: 26px;
  backdrop-filter: blur(16px);
}

.ping-photon {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-cyan);
  box-shadow: 0 0 10px var(--color-cyan);
  display: inline-block;
  animation: photonPulse 1.8s infinite;
}

@keyframes photonPulse {
  0% { transform: scale(0.9); box-shadow: 0 0 0 0 rgba(34, 211, 238, 0.8); }
  70% { transform: scale(1.1); box-shadow: 0 0 0 10px rgba(34, 211, 238, 0); }
  100% { transform: scale(0.9); box-shadow: 0 0 0 0 rgba(34, 211, 238, 0); }
}

.hero-headline {
  font-size: clamp(1.8rem, 3.4vw, 3.15rem);
  font-weight: 950;
  line-height: 1.25;
  letter-spacing: -0.025em;
  margin-bottom: 24px;
  color: var(--text-primary);
  white-space: nowrap;
  word-break: keep-all;
}

.hero-headline .brand-highlight {
  background: var(--accent-gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  white-space: nowrap;
}

.hero-headline .headline-text {
  display: inline-block;
  white-space: nowrap;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 800px;
  margin: 0 auto 38px auto;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin-bottom: 50px;
  flex-wrap: wrap;
}

.hero-telemetry-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 50px;
}

.metric-pill {
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  backdrop-filter: blur(14px);
  text-align: left;
  transition: all var(--transition-fast);
}

.metric-pill:hover {
  border-color: var(--color-cyan);
  box-shadow: 0 0 15px var(--color-cyan-glow);
  transform: translateY(-2px);
}

.metric-val {
  font-size: 1.45rem;
  font-weight: 850;
  color: var(--color-cyan);
  line-height: 1.2;
}

.metric-label {
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-top: 4px;
}

/* Smoked-Glass Telemetry Pane Mockup */
.telemetry-pane-wrap {
  position: relative;
  margin-top: 20px;
}

.smoked-glass-pane {
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-telemetry);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.smoked-glass-pane:hover {
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-glow), var(--shadow-telemetry);
}

.pane-header {
  padding: 16px 26px;
  background: rgba(0, 0, 0, 0.25);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.cluster-status-indicator {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-cyan);
  letter-spacing: 0.03em;
}

.cluster-nodes-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  padding: 24px;
}

.cluster-node-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 18px;
  text-align: left;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
  cursor: pointer;
}

.cluster-node-card:hover {
  border-color: var(--color-cyan);
  transform: translateY(-3px);
  box-shadow: 0 0 20px var(--color-cyan-glow);
}

/* Sub-10ms Load Balance Photon Packet Split animation bar */
.cluster-node-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-cyan), transparent);
  transition: none;
}

.cluster-node-card:hover::before {
  animation: photonSplit 0.6s ease-out infinite;
}

@keyframes photonSplit {
  0% { left: -100%; }
  100% { left: 100%; }
}

.node-flag-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

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

.node-latency-pill {
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--color-cyan);
  background: var(--color-cyan-badge);
  padding: 3px 8px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-telemetry);
}

.node-title-main {
  font-size: 0.96rem;
  font-weight: 750;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.node-route-desc {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* --- 5. Core Advantages Section (3 Smoked-Glass Cards) --- */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.advantage-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 38px 32px;
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(18px);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
  height: 100%;
  position: relative;
  overflow: hidden;
}

.advantage-card:hover {
  transform: translateY(-8px);
  border-color: var(--color-cyan);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.adv-icon-cluster {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-lg);
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 26px;
  color: var(--color-cyan);
  transition: all var(--transition-normal);
}

.advantage-card:hover .adv-icon-cluster {
  background: var(--accent-gradient);
  color: #ffffff;
  box-shadow: 0 0 25px var(--color-cyan-glow);
  transform: scale(1.08) rotate(4deg);
}

.adv-title {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 14px;
}

.adv-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 22px;
  flex-grow: 1;
}

.adv-specs-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 18px;
  border-top: 1px solid var(--border-light);
}

.adv-spec-row {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

.adv-spec-row svg {
  color: var(--color-cyan);
  flex-shrink: 0;
}

/* --- 6. Feature Showcase: Streaming & AI Support Cards --- */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px;
}

.showcase-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 42px;
  box-shadow: var(--shadow-telemetry);
  backdrop-filter: blur(20px);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  overflow: hidden;
  transition: all var(--transition-normal);
}

.showcase-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-cyan);
  box-shadow: var(--shadow-glow), var(--shadow-lg);
}

.showcase-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  margin-bottom: 18px;
  text-transform: uppercase;
}

.pill-stream {
  background: rgba(239, 68, 68, 0.12);
  color: #ef4444;
  border: 1px solid rgba(239, 68, 68, 0.25);
}

.pill-ai {
  background: var(--color-cyan-badge);
  color: var(--color-cyan);
  border: 1px solid var(--border-telemetry);
}

.showcase-title {
  font-size: 1.85rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 14px;
  line-height: 1.3;
}

.showcase-desc {
  font-size: 1.02rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 28px;
}

.platforms-matrix {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 28px;
}

.platform-pill {
  background: var(--bg-telemetry);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.platform-pill:hover {
  background: var(--bg-card-hover);
  border-color: var(--color-cyan);
  transform: translateY(-2px);
  box-shadow: 0 0 12px var(--color-cyan-glow);
}

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

.check-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

.check-item svg {
  color: var(--color-cyan);
  margin-top: 3px;
  flex-shrink: 0;
}

/* --- 7. Pricing Section (Authentic iKuuu VPN Pricing) --- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 44px 34px;
  display: flex;
  flex-direction: column;
  position: relative;
  backdrop-filter: blur(20px);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
}

.pricing-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.pricing-card.popular {
  border: 2px solid var(--color-cyan);
  box-shadow: var(--shadow-glow), var(--shadow-telemetry);
  transform: scale(1.03);
  z-index: 2;
  background: var(--bg-card-hover);
}

.pricing-card.popular:hover {
  transform: scale(1.03) translateY(-8px);
}

.popular-ribbon {
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-gradient);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 900;
  padding: 5px 20px;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  box-shadow: 0 0 20px var(--color-cyan-glow);
  white-space: nowrap;
}

.plan-header {
  margin-bottom: 20px;
  text-align: center;
}

.plan-tier-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  margin-bottom: 8px;
  background: var(--color-cyan-badge);
  color: var(--color-cyan);
  border: 1px solid var(--border-telemetry);
}

.plan-name {
  font-size: 1.5rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 8px;
}

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

.plan-price-wrap {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 4px;
  margin: 20px 0;
}

.price-currency {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--color-cyan);
}

.price-number {
  font-size: 3.4rem;
  font-weight: 950;
  line-height: 1;
  color: var(--text-primary);
  letter-spacing: -0.04em;
}

.price-period {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 600;
}

.plan-features-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin: 24px 0 38px 0;
  flex-grow: 1;
}

.plan-feature-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.93rem;
  color: var(--text-secondary);
}

.plan-feature-item svg {
  color: var(--color-cyan);
  flex-shrink: 0;
}

.plan-feature-item.highlight {
  font-weight: 700;
  color: var(--text-primary);
}

/* Extra Plans Footnote (1元体验包、季付、半年付等真实套餐) */
.pricing-extra-notes {
  margin-top: 40px;
  text-align: center;
  font-size: 0.95rem;
  color: var(--text-muted);
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  border-radius: var(--radius-lg);
  padding: 18px 24px;
  backdrop-filter: blur(12px);
}

.pricing-extra-notes span {
  color: var(--color-cyan);
  font-weight: 700;
}

/* --- 8. User Testimonials Section --- */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.testimonial-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 30px;
  backdrop-filter: blur(16px);
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
}

.testimonial-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-cyan);
  box-shadow: 0 0 25px var(--color-cyan-glow);
}

.testimonial-stars {
  color: #fbbf24;
  display: flex;
  gap: 4px;
  margin-bottom: 16px;
  font-size: 1rem;
}

.testimonial-quote {
  font-size: 0.93rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 22px;
  flex-grow: 1;
}

.testimonial-user {
  display: flex;
  align-items: center;
  gap: 14px;
  padding-top: 16px;
  border-top: 1px solid var(--border-light);
}

.user-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent-gradient);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1rem;
  box-shadow: 0 0 15px var(--color-cyan-glow);
  flex-shrink: 0;
}

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

.user-name {
  font-size: 0.94rem;
  font-weight: 750;
  color: var(--text-primary);
}

.user-role {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* --- 9. FAQ Section (Accordion) --- */
.faq-container {
  max-width: 860px;
  margin: 0 auto;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  backdrop-filter: blur(16px);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.faq-item:hover {
  border-color: var(--border-telemetry);
}

.faq-item.active {
  border-color: var(--color-cyan);
  box-shadow: 0 0 20px var(--color-cyan-glow);
}

.faq-question-btn {
  width: 100%;
  padding: 22px 26px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  text-align: left;
  font-size: 1.08rem;
  font-weight: 750;
  color: var(--text-primary);
  background: transparent;
  gap: 16px;
}

.faq-icon-arrow {
  width: 20px;
  height: 20px;
  color: var(--color-cyan);
  transition: transform var(--transition-normal);
  flex-shrink: 0;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal), padding var(--transition-normal);
  padding: 0 26px;
}

.faq-item.active .faq-answer {
  max-height: 420px;
  padding: 0 26px 24px 26px;
}

.faq-answer p {
  font-size: 0.97rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

/* --- 10. Secondary Pages & '推荐资讯' Layout --- */
.page-hero {
  padding: 72px 0 44px 0;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-light);
  text-align: center;
  position: relative;
  z-index: 2;
}

.page-title {
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 14px;
  letter-spacing: -0.03em;
}

.page-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto;
}

.page-content-wrapper {
  max-width: 900px;
  margin: 60px auto 96px auto;
  padding: 0 24px;
  position: relative;
  z-index: 2;
}

.content-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 44px 40px;
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(20px);
  margin-bottom: 34px;
  transition: all var(--transition-normal);
}

.content-card:hover {
  border-color: var(--border-telemetry);
}

.content-card h2 {
  font-size: 1.55rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: 12px;
}

.content-card h2 svg {
  color: var(--color-cyan);
}

.content-card p {
  font-size: 1.02rem;
  color: var(--text-secondary);
  line-height: 1.78;
  margin-bottom: 16px;
}

.content-card ul {
  margin: 14px 0 22px 20px;
  list-style: disc;
}

.content-card li {
  font-size: 0.98rem;
  color: var(--text-secondary);
  line-height: 1.72;
  margin-bottom: 10px;
}

.content-alert {
  padding: 18px 22px;
  border-radius: var(--radius-md);
  margin: 22px 0;
  border-left: 4px solid var(--color-cyan);
  background: var(--bg-telemetry);
  font-size: 0.96rem;
  color: var(--text-primary);
}

/* Articles / Insights List in telemetry-insights.html */
.article-item {
  border-bottom: 1px solid var(--border-light);
  padding-bottom: 28px;
  margin-bottom: 28px;
}

.article-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
  margin-bottom: 0;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.85rem;
  color: var(--color-cyan);
  font-weight: 700;
  margin-bottom: 10px;
}

.article-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.article-excerpt {
  font-size: 0.98rem;
  color: var(--text-secondary);
  line-height: 1.68;
}

/* --- 11. Footer Section --- */
/* Strictly keeps ONLY the 4 required titles opening in a new tab */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  padding: 56px 0 40px 0;
  text-align: center;
  position: relative;
  z-index: 2;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 44px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  position: relative;
}

.footer-link:hover {
  color: var(--color-cyan);
  background: var(--color-cyan-badge);
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-brand {
  font-weight: 700;
  color: var(--text-secondary);
}

/* --- 12. Responsive Media Queries --- */
@media (max-width: 1024px) {
  .hero-headline {
    font-size: clamp(1.6rem, 3.4vw, 2.5rem);
    white-space: nowrap;
  }
  .advantages-grid,
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-card.popular {
    transform: none;
  }
  .pricing-card.popular:hover {
    transform: translateY(-8px);
  }
  .testimonials-grid,
  .cluster-nodes-grid,
  .hero-telemetry-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .section {
    padding: 64px 0;
  }
  .section-title {
    font-size: 1.95rem;
  }
  .hero-headline {
    font-size: clamp(1.25rem, 4.6vw, 1.8rem);
    white-space: nowrap;
  }
  .hero-subtitle {
    font-size: 1.06rem;
  }
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  .hero-actions a {
    width: 100%;
  }

  .mobile-toggle-btn {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-light);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    transform: translateY(-150%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-lg);
    z-index: 999;
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    font-size: 1.05rem;
    width: 100%;
    text-align: center;
    padding: 10px 0;
  }

  .advantages-grid,
  .showcase-grid,
  .pricing-grid,
  .testimonials-grid,
  .cluster-nodes-grid,
  .hero-telemetry-metrics {
    grid-template-columns: 1fr;
  }

  .platforms-matrix {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-nav {
    gap: 20px;
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .container {
    padding-left: 20px;
    padding-right: 20px;
  }
  .hero-headline {
    font-size: clamp(1.05rem, 4.5vw, 1.35rem);
    white-space: nowrap;
  }
  .platforms-matrix {
    grid-template-columns: 1fr;
  }
}

/* --- 13. In-Depth SEO Article Components --- */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.breadcrumbs a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

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

.breadcrumbs span.separator {
  color: var(--border-telemetry);
}

.article-hero {
  padding: 56px 0 36px 0;
  text-align: left;
  border-bottom: 1px solid var(--border-light);
  background: var(--bg-secondary);
  position: relative;
  z-index: 2;
}

.article-header {
  max-width: 900px;
  margin: 0 auto;
}

.article-h1 {
  font-size: 2.35rem;
  font-weight: 900;
  line-height: 1.3;
  color: var(--text-primary);
  margin: 16px 0 20px 0;
  letter-spacing: -0.025em;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.9rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  padding-bottom: 10px;
}

.article-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Article Layout & Content */
.article-layout {
  max-width: 900px;
  margin: 48px auto 88px auto;
  padding: 0 24px;
  position: relative;
  z-index: 2;
}

/* Table of Contents */
.article-toc {
  background: var(--bg-telemetry);
  border: 1px solid var(--border-telemetry);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  margin-bottom: 40px;
  backdrop-filter: blur(16px);
}

.toc-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-left: 6px;
}

.toc-link {
  font-size: 0.95rem;
  color: var(--color-cyan);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 500;
}

.toc-link:hover {
  text-decoration: underline;
  transform: translateX(4px);
}

/* Article Body Typography */
.article-body {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--text-secondary);
}

.article-body h2 {
  font-size: 1.65rem;
  font-weight: 850;
  color: var(--text-primary);
  margin: 48px 0 18px 0;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: 10px;
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  margin: 28px 0 12px 0;
}

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

.article-body ul, .article-body ol {
  margin: 16px 0 24px 24px;
  list-style: disc;
}

.article-body ol {
  list-style: decimal;
}

.article-body li {
  margin-bottom: 8px;
  line-height: 1.75;
}

.article-body strong {
  color: var(--text-primary);
}

.article-body a {
  color: var(--color-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 600;
}

.article-body a:hover {
  color: var(--color-violet);
}

.article-body blockquote {
  border-left: 4px solid var(--color-cyan);
  background: var(--bg-telemetry);
  padding: 18px 22px;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 24px 0;
  font-style: italic;
  color: var(--text-primary);
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 28px 0;
  font-size: 0.95rem;
}

.article-body th, .article-body td {
  padding: 12px 16px;
  border: 1px solid var(--border-light);
  text-align: left;
}

.article-body th {
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-weight: 750;
}

.article-body tr:nth-child(even) {
  background: var(--bg-tertiary);
}

/* Article Inline CTA Box */
.article-cta-box {
  background: var(--bg-card);
  border: 2px solid var(--border-telemetry);
  border-radius: var(--radius-xl);
  padding: 36px 32px;
  margin: 44px 0;
  text-align: center;
  box-shadow: var(--shadow-telemetry);
  backdrop-filter: blur(20px);
}

.article-cta-box h3 {
  font-size: 1.5rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.article-cta-box p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 24px auto;
}

/* Article FAQ Component */
.article-faq {
  margin-top: 56px;
  padding-top: 36px;
  border-top: 2px solid var(--border-light);
}

.article-faq-title {
  font-size: 1.65rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 24px;
}

.article-faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.article-faq-box {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 22px 24px;
}

.faq-box-q {
  font-size: 1.1rem;
  font-weight: 750;
  color: var(--text-primary);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.faq-box-q svg {
  color: var(--color-cyan);
  flex-shrink: 0;
}

.faq-box-a {
  font-size: 0.96rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Related Reading Component */
.related-section {
  margin-top: 60px;
  padding-top: 36px;
  border-top: 2px solid var(--border-light);
}

.related-title {
  font-size: 1.5rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 22px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.related-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-normal);
}

.related-card:hover {
  border-color: var(--color-cyan);
  transform: translateY(-4px);
  box-shadow: 0 0 16px var(--color-cyan-glow);
}

.related-card-title {
  font-size: 1.05rem;
  font-weight: 750;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.45;
}

.related-card-desc {
  font-size: 0.86rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* Article Portal Grid on telemetry-insights.html */
.insights-portal-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 40px;
}

.portal-article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  backdrop-filter: blur(20px);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.portal-article-card:hover {
  border-color: var(--color-cyan);
  transform: translateY(-6px);
  box-shadow: var(--shadow-telemetry), 0 0 25px var(--color-cyan-glow);
}

.portal-card-top {
  margin-bottom: 20px;
}

.portal-card-tags {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.portal-tag-badge {
  background: var(--color-cyan-badge);
  border: 1px solid var(--border-telemetry);
  color: var(--color-cyan);
  font-size: 0.75rem;
  font-weight: 750;
  padding: 2px 10px;
  border-radius: var(--radius-full);
}

.portal-featured-badge {
  background: linear-gradient(135deg, #f59e0b 0%, #ea580c 100%);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 2px 10px;
  border-radius: var(--radius-full);
}

.portal-card-h2 {
  font-size: 1.35rem;
  font-weight: 850;
  color: var(--text-primary);
  line-height: 1.42;
  margin-bottom: 12px;
}

.portal-card-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.68;
}

.portal-card-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 18px;
  border-top: 1px solid var(--border-light);
  font-size: 0.86rem;
  color: var(--text-muted);
}

.portal-read-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-cyan);
  font-weight: 700;
}

.portal-article-card:hover .portal-read-btn {
  color: var(--color-violet);
  transform: translateX(4px);
}

@media (max-width: 768px) {
  .insights-portal-grid,
  .related-grid {
    grid-template-columns: 1fr;
  }
  .article-h1 {
    font-size: 1.85rem;
  }
}